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MP Board Class 12th Chemistry Important Questions Chapter 3 Electrochemistry

Electrochemistry Important Questions

Electrochemistry Very Short Answer Type Questions

Question 1.
Can you store copper sulphate solutions in a zinc pot? (NCERT)
Answer:
No, copper sulphate solution cannot be stored in a zinc container because value of standard electrode potential of zinc is less than of copper. Thus, zinc is a stronger reducing agent than copper.
Zn + Cu²⁺ → Zn²⁺ + Cu.
E_cell = F_cathode – F_anode
= 0.34-(-0.76)
= +1.1V.

Question 2.
Why does the conductivity of a solution decrease with dilution? (NCERT)
Answer:
Because number of ions per cm³ decreases.

Question 3.
Explain, how rusting of iron is envisaged as setting up of an electrochemical cell? (NCERT)
Answer:
Formation of carbonic acid takes place on the surface of iron

Question 4.
Arrange the following metals in the order in which they displace each other from the solution of their salts. Al, Cu, Fe, Mg and Zn. (NCERT)
Answer:
A metal with lesser standard potential (more reactive) can displace the other metal from solution of its salts.

Question 5.
Write the definition of Electrochemical cell.
Answer:
System in which chemical energy is converted to electrical energy by oxidation reduction is known as electrochemical cell or voltaic cell.

Question 6.
What is Electrode potential?
Answer:
The potential difference developed between the electrodes and electrolyte of an electrolytic cell is known as Electrode potential.

Question 7.
What is a strong electrolyte ? Write two examples.
Answer:
Electrolyte which completely dissociate in aqueous solution are known as strong electrolyte.
Example : NaCl, KCl, NH₄Cl etc.

Question 8.
What is meant by standard electrode potential?
Answer:
Standard electrode potential (E°) of a half cell is the potential difference when one electrode is dipped in molar solution of its ion at 298 K. If electrode is gaseous the pressure of gas must be one atmosphere. In IUPAC system, reduction potential are known as standard electrode potential.

Question 9.
Write Ohm’s law.
Answer:
According to Ohm’s law, “It states that potential difference across the conductor is directly proportional to the current (I) flowing through it” i.e.,
Mathematically, it can be written as:
I ∝ V
V = IR (R = Resistance, unit = ohm, Q)

Question 10.
What is cell constant?
Answer:
For a conductivity cell, the ratio of distance between two electrodes (l) and area of cross-section of electrode (A) is called as cell constant.
Cell constant = \(\frac {1}{A}\) or x = \(\frac {1}{A}\)
Unit of cell constant = cm^-1

Question 11.
What is galvanization? Explain.
Answer:
Iron is coated with the layer of zinc to protect it from rusting. This process is known as galvanization. The galvanized iron articles keep their lustre due to the coating of invisible protective layer of basic zinc carbonate, (ZnCO₃) or zinc hydroxide (Zn(OH)₂).

Question 12.
Why is it not possible to determine the Electrode potential of a single half cell?
Answer:
Because Electromotive force of two electrodes containing a complete circuit can be measured.

Question 13.
Write the unit of specific conductance.
Answer:
ohm^-1metre^-1= Ω^-1m^-1 = Sm^-1

Question 14.
What is the relation between equivalent conductance and specific conductance?
Answer:
Λ^c_eq = \(\frac {1ooo×k}{c}\)

Electrochemistry Short Answer Type Questions

Question 1.
Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration. (NCERT)
Answer:
Conductivity:
Conductivity of a solution is defined as the conductance of a solution of 1 cm length and having 1 sq. cm as the area of cross-section.

Molar conductivity:
Molar conductivity of a solution at a dilution (V) is the conductance of all the ions produced from one mole of the electrolyte dissolved in V cm³ of the solution when the electrodes are one cm apart and area of cross – section of the electrodes is so large that the whole of the solution is contained between them. It is usually represented by Λ_m.

Variation with concentration:
The conductivity of a solution (Both for strong and weak electrolytes) decreases with decrease in concentration of the electrolyte i.e., on dilution. This is due to the decrease in the number of ions per unit volume of the solution on dilution. The molar conductivity of a solution increase in the decrease in concentration of the electrolyte i.e., on dilution. This is due to the decrease in the number of ions per unit volume of the solution on dilution.

The molar conductivity of a solution increases with decrease in concentration of the electrolyte. This is because both number of ions as well as mobility of ions increases with dilution. When concentration approaches zero, the molar conductivity is known as limiting molar conductivity.

Question 2.
What is salt bridge ? Write its two functions.
Answer:
‘U’ shaped tube filled with KCl or KNO₃ in Agar – Agar solution or gelatin, is known as salt bridge. It connects the two half cell.

Functions:

1. It allows the flow of current by completing the circuit.
2. It maintains the electrical neutrality.

Question 3.
Write difference between Metallic conduction and Electrolytic conduction.
Answer:
Differences between Metallic conduction and Electrolytic conduction:
Metallic conduction:

• Metallic conduction takes place by movement of electrons.
• There is no chemical change.
• There is no transfer of matter.
• In metallic conduction conductivity decreases with increase in temperature.

Electrolytic conduction:

• Electrolytic conduction takes place by movement of ions.
• Due to chemical change decomposition of electrolyte takes place.
• Transfer of matter takes place as ions.
• In electrolytic conduction conductivity
• increases with increase in temperature.

Question 4.
What are the difference between emf (Cell potential) and potential difference:
Answer:
Differences between EMF (Cell potential) and Potential difference
EMF (Cell potential):

• It is the potential difference between the two terminals of the cell when no current is flowing in the circuit, i.e., in an open circuit.
• It is the maximum voltage which can be obtained from a cell.
• It can be measured by potentiaometrie method.
• Work performed by electromotive force is the maximum work done by a cell.
• It is responsible for continuous flow of current in electric circuit.

Potential difference:

• It is the difference of the electrodes potentials of the two electrodes when the cell is sending current through the circuit.
• It is the less than the maximum voltage as it is the difference of electrode potential.
• It can be measured by simple voltmeter also.
• Work performed by potential difference is less than the maximum work done by a cell.
• It is not responsible for the continuous flow of current in circuit.

Question 5.
What is specific conductance? Give its unit.
Answer:
Specific conductivity:
The reciprocal of resistivity is called specific conductivity. It is defined as the conductance between the opposite faces of one centimeter cube of a conductor. It is denoted by K (kappa).
Thus.
K = \(\frac {1}{ρ}\) (∵ ρ = \(\frac {RA}{l}\)
K = \(\frac {1}{R}\) × \(\frac {1}{A}\)
where, R = Resistance, A = Cross – sectional area of electrodes and l = Length between the electrodes.
Unit = K = \(\frac {1}{ohm}\) × \(\frac { cm }{ { cm }^{ 2 } } \) = ohm^-1 cm^-1
S.I. Unit Scnf1 or Ohm^-1 cm^-1.

Question 6.
What is resistivity of any solution?
Answer:
Resistivity:
When current flow in the solution through two electrodes the resistance is proportional to length and inversely proportional to cross – sectional area A.
R ∝\(\frac {l}{A}\)
or R = ρ\(\frac {l}{A}\)
or ρ = R × \(\frac {A}{l}\)
The constant p (rho) is called resistivity or specific resistance.
Unit: If Z is expressed in cm, A in cm² and R in ohm, the unit of resistivity will be
\(\frac { c{ m }^{ 2 }\times ohm }{ { cm } }\) = ohm cm
If l = 1 cm and A = 1 cm² then ρ = R
or Resistivity of any solution is the resistance of 1 cm cube.

Question 7.
What is equivalent conductance?
Answer:
Equivalent conductance:
“Conductance of total ion produced by one gram equivalent of electrolyte in the solution is called equivalent conductance.” It is denoted by Λ_eq.

Question 8.
What is molar conductance?
Answer:
Molar Conductivity:
The molar conductivity of a solution at definite concentration of (or dilution) and temperature is the conductivity of that volume which contains one mole of the solute and is placed between two parallel electrodes 1 cm apart and having sufficient area to hold whole of the solution. It is denoted by Λ_m.
Mathematically,
Λ m=k × V .. (1)
Where, V is the volume in ml in which one gram mole of substance is dissolved.
If M is molarity or m moles are dissolved in 1000 ml.

Question 9.
Define cell constant. Develop a relation between specific conductance and cetfconstant.
Answer:
Cell constant:
In any conductive cell, the distance between two electrodes and surface area of .electrode A are constant. The ratio of l and a is called cell constant i.e.
cell constant = \(\frac { l(cm) }{ a{ ({ cm) }^{ 2 } } }\)
Unit of cell constant is cm^-1 and it is generally expressed by x.

Relation between specific conductance and cell constant:
For a conductor, the resistance R is directly proportional to length R and inversely proportional to area of crosssection of electrolyte.

Question 10.
What are the factors which influence the electrical conductance of electrolytes?
Answer:
The main factor which influence the electrical conductivity are following :
1. Temperature : It influence following interactions.

• Interionic attractions : It depends upon the solute-solute interactions. Which is found between the ions of solute.
• Solvation of ions : It depends upon solute-solvent interactions. It is relation between ions of solute and solvent molecules.
• Viscosity of solvent : It depends upon solvent-solvent interactions. Solvent molecules are related with each other.

With increase in temperature all these three effects decrease and average kinetic energy of ions increases. Thus, with increase of temperature, resistance of solution decreases and hence conductance increases.

2. Nature of electrolyte:
The conductance of solution depends upon the nature of electrolyte. On the basis of conductance measurement electrolytes are classified as strong electrolyte and weak electrolyte. Strong electrolytes have high value of conductance even at higher concentration also.

3. Dilution or concentration:
It is main factor which influence electrical conductance. Effect of dilution or concentration can be studied indivisually in equivalent conductance, specific conductance and molar conductance. But for a general concept of electrical conductance of solution as the concentration is lowered or dilution increases, electrical conductance of whole solution increases.

Question 11.
What is an Electrolytic cell and how does it work?
Answer:
Electrolytic cells:
In these cells electric current is supplied through an external source, as a result of which chemical reactions take place which is called electrolysis like Electrolysis of water, NaCl, Al₂O₂ etc. For example in Solvay trough cell electrode is immersed in sodium chloride solution and electric current is passed due to which NaCl electrolyses. At mercury cathode sodium is released and at anode chlorine is released. Sodium forms amalgam with mercury and is taken out of the cell.

Electrolysis : NaCl → Na⁺ + Cl^–

At cathode : Na⁺ + e^– → Na
Na + Hg → (Na – Hg) Amalgam

At anode : Cl^– – e^– → Cl
Cl + Cl → Cl₂
In electrolytic cell, electricity is supplied through an external source. Thus, positive pole is anode and negative pole is cathode.

Question 12.
What is meant by electromotive force of an electrochemical cell?
Answer:
The difference in electrode potentials of the two electrodes of an electrochemical cell is known as electromotive force or cell potential. It is expressed in volt. Due to difference in potential electric current flows from an electrode of lower potential to an electrode of higher potential. EMF of the cell can be expressed in terms of reduction potential as :

Cell potential = Standard electrode potential of R.H.S. electrode – Standard electrode potential of L.H.S. electrode
Thus, E_cell = E_redn. (right) – E_redn. (left)
E_cell = E_redn.(cathode) – E_redn.(anode)
EMF of a cell is measured by connecting the voltmeter between the two electrodes of a cell. EMF of a cell depend on the concentration of solutions of both half cells and nature of the two electrodes. For example, In Daniel cell, concentration of CuSO₄ and ZnSO₄ solutions in the two half cells is 1M and at 298 K EMF of the cell is 1.10 volt.

Question 13.
What is electrochemical series? Write its application.
or, Write application and characteristics of Electrochemical series.
Answer:
The series in which elements are arranged in increasing order of standard electrode potential is known as electrochemical series.

Applications of Electrochemical Series :

1. Determination of EMF of cell:
EMF of a cell is the difference between standard reduction potential E° of its cathode and anode.
E°_cell = E°_cathode – E°_anode
If e.m.f. is positive, then the cell reaction proceeds in the required direction and if e.m.f of the cell is negative the cell reaction proceeds in the opposite direction.

2. Calculation of Equilibrium constant of cell:
Equilibrium constant k of the cell can be calculated by determining the e.m.f of the cell by the help of Electrochemical series.
Characteristics:

• Metals which are above hydrogen in the series react with acids to produce hydrogen gas.
• This series represents the standard electrode potential elements i.e, tendency to accept electrons. Elements of negative E° possess the tendency to loose electron.
• Elements which come before in the series displace the metals placed below the series, from their salts.
• At the top of the series strongly reducing elements are present because they possess the tendency to loose electrons.
• Example : Li and below strongly oxidizing like F possess the tendency to accept electron.

Question 14.
What do you understand by standard potential of a half cell? How is the standard potential of a half cell determined?
Answer:
Standard electrode potential E° of an electrode (half cell) is that value of potential when all the substances are at one atmospheric pressure and activity of the species present in the form of reactant and product is one unit. Standard electrode potential (E°) is measured by the use of potentiometer.
E°_cell = E°_R – E°_L = E°_{half cell} – E°_ref

Question 15.
Differentiate between Electrochemical cell (Galvanic cell) and Electrolytic cell.
Answer:
Differences between Electrochemical and Electrolytic cells:
Electrochemical cell:

• It is a device to convert chemical energy into electrical energy.
• It consists of two electrodes in different compartments joined by a salt bridge.
• Redox reactions occurring in the cell are spontaneous.
• Free energy decreases with operation of cell, i.e., ∆G <0.
• Useful work is obtained from the cell.
• Anode works as negative and cathode as positive electrodes.
• Electrons released by oxidation process at anode go into external circuit and pass to cathode.
• To set – up this cell, a salt bridge/porous pot is used.

Electrolytic cell:

• It is a device to convert electrical energy into chemical energy.
• Both the electrodes are in same solution.
• Redox reactions occurring in the cell are non – spontaneous.
• Free energy increases with operation of cell, i.e., ∆G >0.
• Work is done on the system.
• Anode is positive and cathode is negative.
• Electrons enter into cathode electrode from external source and leave the cell at anode.
• No salt bridge is used in this cell.

Electrochemistry Long Answer Type Questions

Question 1.
What is standard hydrogen electrode? How is it prepared?
Answer:
Standard hydrogen electrode:
This consists of gas at 1 atmospheric pressure bubbling over a platinum electrode immersed in 1 M HCl at 25°C (298 K) as shown in figure. The platinum electrode is coated with platinum black to increase its surface. The hydrogen electrode thus constructed forms a half cell which on coupling with any other half cell begins to work on the principle of oxidation or reduction. Electrode depending upon the circumstances works both as anode or cathode.

Cell reaction of standard hydrogen electrode (SHE) when it acts as anode is
H_2(g) → 2H²⁺ + 2e^–
It is as represented as
H_2(g)(1 atm) Pt |H3O⁺_aq(1.0M)
When it acts as cathode, the cell reaction is
2H⁺ + 2e^– → H_2(aq)
and it is represented as
H₃O⁺_(aq)(1.0M)|(latm)Pt
Standard hydrogen electrode (SHE) is arbitrarily assigned a potential of zero.

Question 2.
Derive Nernst Equation for single electrode potential.
Answer:
Value of standard electrode potential given in electrochemical series is applicable only when the concentration of electrolyte is 1M and temperature is 298 K. But in electrochemical cells the concentration of electrolyte is not definite and electrode potential depends on concentration and temperature. In such condition single electrode potential can be expressed by Nernst equation.
For a reduction half reaction, Nernst equation can be expressed as follows:

Where, E = Reduction electrode potential
E° = Standard electrode potential (Mⁿ⁺+concentration 1M and at 298 K)
R = Gas constant = 831 JK^-1mol^-1, T = Temperature (in Kelvin) = 298 K
n = Valency of metal ion, F = 1 Faraday (96,500 coulomb)
On substituting the values : E = E°+\(\frac {0.059}{n}\) log₁₀[M⁺] … (2)
Equation (2) is Nemst equation for single electrode potential.

Question 3.
Write the Faraday’s laws of electrolysis.
Answer:
Faraday’s first law of electrolysis:
The law states that, “The mass of any substance deposited or liberated at any electrode is directly proportional to the quantity of electricity passed.”
Thus, if W gm of the substance is deposited on passing Q coulomb of electricity, then W ∝Q or W = ZQ
Where, Z is a constant of proportionality and is called electrochemical equivalent of the substance deposited. If a current of I ampere is passed for t second, then Q = I x t. So that,
W = Z x Q = Z x l x t
Thus, if Q = 1 coulomb, I = 1 ampere and t = 1 second, then W = Z. Hence, electrochemical equivalent of a substance may be defined as, “The mass of the substance deposited when a current of one ampere is passed for one second.”
As one Faraday (96500 C) deposits one gram equivalent of the substance, hence electrbchemical equivalent can be calculated from the equivalent mass.
i.e., Z = \(\frac {Equivalent mass of the substance}{96500}\)

Faraday’s second law of electrolysis:
It states that, “When the same quantity of electricity is passed through solutions of different electrolytes connected in series, the weight of the substances produced at the electrodes are directly proportional to their equivalent mass.”

For example, for CuSO₄ solution and AgNO₃ solution connected in series, if the same quantity of electricity is passed, then

Question 4.
What is rusting of iron? Describe Electrochemical theory of rusting. An^Corrosion : Process by which the layers of undesirable compounds are formed on the surface of a metal on its exposure to atmospheric condition are called corrosion. Rusting of iron is an example of corrosion, chemically it is Fe₂O₃xH₂O.

Electrochemical theory of rusting :
Anode reaction:
On one spot of iron sheet, oxidation takes place and this spot behaves as an anode.
Fe_(s) → Fe²⁺_(aq) + 2e^–; E° = + 0.44 V.
The electrons which are released at this spot travel through the metal and reach another spot on the metal which acts as cathode. These electrons cause the reduction of oxygen in the presence of hydrogen ions (H⁺). H⁺ ions are formed due to decomposition of carbonic acid formed by dissolution of CO₂ in H₂O.
H₂O + CO₂ → H₂CO₃
H₂CO₃ ⇌ 2H₊ +CO₃^2-+

Cathode reaction:
O_2(g) + 4H⁺_(aq) → 2H₂O; E° = 1.23V

Overall reaction:
2Fe_(s) + O_2(g) + 4H⁺_(aq) → 2Fe²⁺ +2H₂O_(l); E°_cell = 1.67V

Fe2Fe²⁺ ion formed travel on the surface of article and react with more oxygen in the presence of H₂O. This results in the formation of ferric oxide.

4Fe²⁺_aq + O_2(g) + 4H₂O_(l) → 2Fe₂O₃ + 8H⁺_aq

Water present causes the hydration of ferric oxide formed.
Fe₂O₃ + XH₂O → Fe₂O₃.xH₂O (rust) Thus, rust is formed.

Question 5.
What is Kohlrausch law? Give its two applications.
Answer:
Kohlrausch in 1875 gave a generalisation known as Kohlrausch’s law, “At infinite dilution when the dissociation of the electrolyte is complete, each ion makes a definite contribution towards molar conductance of the electrolyte irrespective of the nature of the other ion with which it is associated.”
Or
“The value of molar conductance at infinite dilution is given by the sum of the contributions of ions (cation and anion).”
Mathematically,

Where, λ^∞₊ and λ^∞_– are ionic contributions or ionic conductances of cation and anion while v₊ and v_–are the number of cations and anions in the formula unit of electrolyte.

Applications of Kohlrausch’s law:
(i) Calculation of molar conductance at infinite dilution for weak electrolytes :
Molar conductance or equivalent conductance of weak electrolytes cannot be obtained graphically by extrapolation method, since these are feebly ionized. Kohlrausch’s law enables indirect evaluation in such cases. For example, molar conductances of acetic acid can be obtained from the knowledge of molar conductances at infinite dilution of HCl, CH₃COONa and NaCl which are strong electrolytes. From Kohlrausch’s law, it is clear that

(ii) Determination of degree of dissociation:

Question 6.
Draw a labelled diagram of Daniel cell and explain ceLl reaction.
Or, Draw a labelled diagram of electrochemical cell and write cell reaction.
Answer:
Electrochemical cell:
In the redox reactions, the transfer of electrons between oxidizing and reducing agents occurs through wire and thus chemical energy changes into electrical energy. The device on which chemical energy changes into electricaL energy is called electrochemical cell. These are also known as galvanic or voltaic cells. Working of these cells can be understood with the example of Daniel cell.

Daniel çell:
In this cell, Zn rod is dipped in ZnSO₄ solution and Cu rod in copper sulphate solution. Both solutions are connected through KCL salt bridge. When Zn and Cu electrodes are connected by wire and galvanometer, flow of electrons from Zn to Cu occurs. Zinc atoms change into Zn²⁺ and electrons reach at Cu electrode, where Cu²⁺ changes into Cu metal and this copper deposits on electrode.

Electrochemistry Numerical Questions

Question 1.
Calculate the potential of hydrogen electrode in contact with a solution whose pH is 10. (NCERT)
Solution:
If pH of solution is 10 means its [H⁺] ion concentration is 10^-10 M.
Using, E_cell = E°_cell – \(\frac {0.059}{n}\) log\(\frac { 1 }{ [{ H }^{ + }] }\)
Here E°_cell = 0, n =2, [H⁺] = 10^-10
∴E_cell = 0 – \(\frac {0.059}{2}\) log \(\frac { 1 }{ [{10}^{ -10 }] }\) = -0.59V

Question 2.
Calculate the standard cell potentials of galvanic cells in which the following reactions take place : (NCERT)
1. 2Cr_(s) + 3Cd²⁺_(aq) → Cr³⁺_(aq) + 3Cd
2. Fe²⁺_(aq) +Ag⁺_(aq) → Fe³⁺_(aq) + Ag_(s). Calculate the ∆_rG°, and equilibrium constant of the reactions.
Solution:
1. E°_cell = E°_Ecathode – E°_Eanodg
= – 0.40 -(-0.74) = +0.34V
∆G° = -nFE° = -6 x 96500 x 0.34
= -196860J = -196.86kJmol^-1
∆G° =-2.303 RT log K
– 196860 =-2.307 x 8.314 x 298 log K
or log K = 35.5014 or K
= Antilog 34.5014 = 3.19 x 10³⁴

2. E°_cell = E°_Ecathode – E°_Eanodg
= 0.80 – (0.77) = +0.03V
∆G° = -nFE° = -1 x 96500 x 0.03
= -2895Jmol^-1
= – 2-895 kJmol^-1
∆G° = -2-303 RT log K
– 2895 Jmol^-1 = -2.303 x 8.314 x 298 log K or
or K = Antilog of 0.5074 = 3.22.

Question 3.
Using the standard electrode potentials given in Table 3.1 (in your Text-book), predict if the reaction between the following is feasible : (i) Fe³⁺_(aq) and I^–_(aq)
(ii) Ag⁺_(aq) and Cu_s
(iii) Fe³⁺_(aq) and Br^–_(aq)
(iv) Ag_sand Fe³⁺_(aq)
(v) Br_2(aq) and Fe²⁺_(aq). (NCERT)
Answer:
A reaction is feasible if EMF of the cell is ⁺ve.
Cathode : At which reduction occurs.
Anode : At which oxidation occurs.

Question 4.
If specific conductance of 0.02 mol L^-1 KCI solution at 298 K is 2.48 x 10^-2 Ω^-1cm^-1, then calculate its molar conductance.
Solution:
K = 2.48 x 10^-2 cm^-1, C = 0.02 mol L^-1
Λ_m = \(\frac { 1000k }{ { C }_{ m } }\)
= \(\frac { 1000×2.48×{ 10 }^{ -2 } }{ 0.02 }\)
= 124 Scm² mol^-1

Question 5.
What are weak electrolytes? Give one example. Find out molar conductivity of LiBr aqueous solution infinite dilution when joint conductance of Li^-1 ion and Br^-1 ion are 38.7 Scm² mol^-1 and 78.40 Scm² mol^-1 respectively.
Solution:
Weak electrolytes : These are the substances which dissociate only to a small extent.
Examples: CH₃COOH,NH₄OH
Λ_∞ LiBr = Λ_∞ Li⁺ + Λ_∞ Br^–
Given that,
Λ_∞ Li⁺ = 38.7Scm² mol^-1
Λ_∞ Br^– = 78.40 Scm² mol^-1
Λ_∞ LiBr = 38.7 + 78.40
Λ_∞ LiBr = 117.10Scm²mol^-1

Question 6.
What are strong electrolytes? Find out the molar conductivity of aqueous solution of BaCl₂ at infinite dilution when ionic conductance of Ba⁺² ion and Cl^– ion are 127.30 Scm² mol^-1 and 76.34 Scm² mol^-1 respectively.
Solution:
Strong electrolytes : These are substances which dissociate almost completely into ions under all dilutions.
Examples : NaCl,HCl,CH₃COONa
Λ_∞ BaCl₂ = Λ_∞ Ba²⁺ + 2 Λ_∞ Cl^–
Given that,
Λ_∞ = 127.30Scm²⁺mol^-1
Λ_∞ Cl^-1 = 76.34Scm²⁺mol^-1
Λ_∞ BaCl₂ =127.30+2(76.34)
= 127.30 + 152.68
= 279.98 Scm²⁺mol^-1

MP Board Class 12th Chemistry Important Questions

MP Board Class 12th Chemistry Important Questions Chapter 2 Solutions

Solutions Important Questions

Very Short Answer Type Questions

Question 1.
Write formula of van’t Hoff factor ‘i’
Answer:
van’t Hoff factor, i = \(\frac {Observed value of colligative property}{Calculated value of colligative property}\)

Question 2.
Write down van’t Hoff equation. Give formula used for calculating molecular mass with its help.
Answer:
van’t Hoff equation, πV = nRT
or π = \(\frac { nRT}{V}\)
or π = \(\frac { WRT}{MV}\)
or π = \(\frac { WRT}{πV}\)
Where, W is mass of solute, R is Solution constant, T is temperature, n is osmotic pressure and V is volume of Solution.

Question 3.
Define Normality.
Answer:
Number of gram equivalent of solute present in one litre of Solution: is called normality. It is represented by N.
Normality (N) = \(\frac {Number of gram equivalent of solute}{Volume of Solution: in litres}\)
or N = \(\frac {Mass of solute in grams }{Equivalent mass of solute}\) x \(\frac { 1000}{ Volume of Solution: in ml }\)
∵ [No. of gram equivalent =\(\frac {Mass of solute in grams}{Equivalent mass of solute}\)]
Normality of a Solution changes with temperature as it is based on mass – volume relationship and volume changes with change in temperature.

Question 4.
Differentiate between Molarity and Molality.
Answer:
Differences between Molarity and Molality :
Molarity (M):

• Molarity involves the total volume of Solution.
• In molarity, gram moles of solute are dissolved in 1 litre of Solution:.
• Molarity changes with temperature because volume changes with temperature.

Molality (m):

• Molality involves the mass of solvent.
• In molality, gram moles of solute are dissolved in 1 kg of solvent. Here volume of Solution is not considered.
• Molality is independent of temperature as it takes mass into consideration.

Question 5.
Explain the following term : Parts per million.
Answer:
Parts per million:
When a solute is present in very minute amounts (in traces), the concentration is expressed in parts per million abbreviated as ppm. The parts may be of mass or volume. It is the parts of a component per million parts of the Solution.
i.e., ppm = \(\frac {Mass of component A}{Total mass of Solution:}\) x 10⁶
or ppm = \(\frac {Volume of component A}{Total volume of Solution:}\) x 10⁶
Where, ppm. is the concentration of component A in parts per million.

Question 6.
What role does the molecular interaction play in a Solution: of alcohol and water? (NCERT)
Answer:
Alcohols dissolve in water due to formation of inter – molecular H – bonding with water.

Question 7.
Why do gases always tend to be less soluble in liquids as the temperature is raised? (NCERT)
Answer:
Gas + Liquid ⇌ Dissolved gas   ∆ H = – ve
The dissolution of a gas in a liquid is exothermic process. Therefore in accordance with Le – Chatelier’s principle with increase in temperature, the equilibrium shifts in back-ward direction. Therefore, the solubility of gas in Solution decreases with the rise in temperature.

Question 8.
State Henry’s. (NCERT)
Answer:
Henry’s law:
According to this law, ‘The mass of a gas dissolved per unit volume of a solvent at constant temperature, is proportional to the pressure of the gas with which the solvent is in equilibrium’. Let in unit volume of solvent, mass of the gas dissolved is m and equilibrium pressure be P, then m ∝P or m = KP, where K is a constant.

Question 9.
What are colligative properties?
Answer:
The physical properties of Solution which depend on the number of total particles present in Solution and the ratio of number of particles of solute not on the nature of solute particles are known as colligative properties.

Question 10.
Give an example of Solution: of solid in solid.
Answer:
Mixture of copper and gold is an example of solid in solid.

Question 11.
On dissolving ethanoic acid in benzene, experimental molecular mass of ethanoic acid is generally found to be double. Why?
Answer:
On dissolving ethanoic acid in benzene, it dimerizes due to the formation of hydrogen bond. Thus, its experimental value is generally found to be double.

Question 12.
What is vapour pressure? What is the effect of temperature on it?
Answer:
Pressure exerted by the vapours on the surface of a liquid at the state of equilibrium is known as vapour pressure. On increasing the temperature vapour pressure increases.

Question 13.
What type of deviation is represented by acetone and CS₂ Solution?
Answer:
Positive deviation.

Question 14.
Why is CaCl₂ used for clearing off snow from the roads?
Answer:
On adding CaCl₂, freezing point of water decreases. Therefore, CaCl₂ is used for clearing off snow from the roads.

Question 15.
Based on solute – solvent interactions, arrange the following in order of increasing solubility in n – octane and explain :
Cyclohexane, KCl, CH₃OH, CH₃CN.
Answer:
For solubility we know Tike dissolves like’, n – octane is a non – polar solvent, hence non-polar compounds will be more soluble.
KCl < CH₃OH < CH₃CN < Cyclohexane.

Question 16.
What is transition temperature?
Answer:
The temperature at which the nature of solubility changes (i.e., first it increases, then decreases) is known as transition temperature. Solubility of sodium sulphate in water increases upto 32.4, then it starts decreasing. Thus, 32.4°C is the transition temperature of sodium sulphate.

Question 17.
Define molarity and molality. (NCERT)
Answer:
Molarity “is defined as number pf gram mole§ of solute dissolved in a litre of Solution. It is denoted by M.
Molality (M) = \(\frac {Mass of solute in gram per litre}{ Molecular mass of solute}\)

Molality is defined as number of moles of solute present in a kilogram (1000 gram) of solvent. It is denoted by m.
Molality (m) = \(\frac {Mass of solute in kg of solvent}{Gram molecular mass of solute}\)

Solutions Short Answer Type Questions

Question 1.
Write down Raoult’s law.
Answer:
The vapour pressure of a solution containing non – volatile solute is directly pro – portional to the mole fraction of the solute.
Mathematically,
\(\frac { { X }_{ A } }{ { X }_{ A }+{ X }_{ B } } \) = \(\frac { P{ A }^{ 0 } }{ { P }_{ A }+{ P }_{ B } } \)
Where, P⁰_A = Vapour pressure of pure solvent, P_A = Vapour pressure of solvent in solution, X_B = Mole fraction of solute.

Question 2.
What is Azeotropic mixture? They are of how many types? (MP 2018)
Answer:
Azeotropic mixture is the mixture of liquids which boil at one temperature with-out any change in composition. For example, at the composition of 95 6% alcohol and 4.4% water. It form an azeotropic mixture which boils at 78.13°C. Components of this mixture cannot be separated fully by fractional distillation.

They are of two types :
1. Low boiling azeotropic mixture:
Such Solutions which represent positive deviation towards Raoulfs law i.e. their vapour pressure is high thus their boiling point is low are known as low boiling azeotropic mixture.

Example:

• CS₂ + Acetone
• C₂ H₅ OH + n – hexane.

2. High boiling azeotropic mixture:
Such Solutions which represent negative deviation towards Raoult’s law i.e. their vapour pressure is low thus their boiling point is high are known as high boiling azeotropic mixture.

Example:

• Acetone + Chloroform
• Ether + Chloroform.

Question 3.
What are ideal and non – ideal Solutions? Explain with example.
Answer:
Ideal Solutions:
Ideal Solutions are those Solutions in which Raoult’s law can be applied completely for all concentrations of the Solutions and at all temperatures.

Condition for ideal Solutions are following :

1. P_A = P_A⁰ X _A and P_B= P⁰_B X B
2. ∆V_mixing = 0 and
3. ∆H_mixing = 0 and

Example:
C₂H₅Br + C₂H₅Cl, C₆H₆ + C₆H₅CH₃, CCl₄ + SiCl₄etc.

Non – ideal Solutions:
Solutions in which Raoult’s law cannot be applied completely for all concentrations and temperatures are called non – ideal Solutions.
For these Solutions:

1. P_A ≠ P⁰_A X_A and p_B ≠ P⁰_BX_B 
2. ∆V_mixing ≠ 0 and
3. ∆H_mixing ≠ 0 and

Example:
Benzene + Acetone, CHCl₃ + HNO₃ etc.

Question 4.
Establish van’t Hoff Solution: equation. (MP 2018)
Answer:
Osmotic pressure of dilute Solution of a non – volatile solute is proportional to absolute temperature of the Solution at constant concentration. This is known as van’t Hoff law.
π ∝ T .. (1)
Derivation : Osmotic pressure n of a Solution: is directly proportional to a molar concentration.
π ∝ C
By eqn.(l) and eqn.(2) π ∝ C (T is constant) .. (2)
or π = RCT .. (3)
Where, R = Gas constant
or
C = \(\frac {1}{V}\)
π = \(\frac {RT}{V}\) .. (4)
πV = RT .. (5)
This is known as van’t Hoff Ideal Solution equation.

Question 5.
Define the following:

1. Molal elevation boiling point constant.
2. Molal freezing point depression constant. (MP 2018)

Answer:
1. Molal elevation boiling point constant : Molal elevation constant can be defined as “The elevation in boiling point of the Solution in which 1 gm of solute is dissolved in 1000 gm of solvent.”
∴ Elevation in boiling point
∆ T_b ∝ m
∆ T_b = K_bm
m= 1, ∆ T_b = K_b
Where K_b = Molal boiling point elevation constant.

2. Molal freezing point depression constant : Molal depression constant may be defined as “The depression in freezing point for 1 molal Solution: i.e., Solution: in which 1gm mole of solute is dissolved in 1000 gm of solvent.”
∴ Depression in freezing point
∆ T_f ∝ m
∆ T_f = k_f
If m = 1, ∆ T_f = k_f
Where K_f = Molal freezing point depression constant.

Question 6.
What is Raoult’s law? Establish its mathematical expression.
Or,
What is Raoult’s law? How can molar mass of a non – volatile solute be determined with its help?
Answer:
Raoult’s law:
For a Solution in which solute is non – volatile, the Raoulf s law may be stated as following :
“At any constant temperature, vapour pressure of solvent collected above the Solution of non – volatile solute, is directly proportional to the mole fraction of solute.” If a non – volatile solute is added to a volatile solvent, the vapour pressure of the solvent decreases. The vapour pressure of the solvent is directly proportional to its mole fraction. As the solute is non – volatile, the vapour pressure of the Solution (P) will be equal to the vapour pressure of the solvent (PA).
P = P_A ∝ X_A
or P_A=KX_A .. (1)
Where, K = Proportionality constant.
Apply eqn. (1) for pure solvent if X_A= 1 and P_A = P⁰_A
Then, P⁰_A = K x 1 .. (2)
Where, p⁰_A= Vapour pressure of pure solvent.
Putting the value of K from eqn. (2) in eqn. (1),
P_A=P⁰_AX_A .. (3)
Where, X_A is the mole fraction of the solvent in the Solution.
The mole fraction of solute is represented as XB.
So, X_A+X_B=1
or X_A= 1 – X_B .. (4)
From eqns. (3) and (4),
P_A= P⁰_A(1-X_B) = P⁰ – P⁰_AX_B
X_B = \(\frac { { P }_{ A\quad }^{ 0 }-\quad { P }_{ A } }{ { P }_{ A }^{ 0 } } \)
P⁰_A is lowering in vapour pressure and \(\frac { { P }_{ A\quad }^{ 0 }-\quad { P }_{ A } }{ { P }_{ A }^{ 0 } } \) is relative lowering in vapour pressure.

On the basis of equation (5) Raoult’s law can be defined as “The relative lowering in vapour pressure of a Solution containing non – volatile solute is equal to mole fraction of solute”.

Question 7.
Give relation between elevation in boiling point and molecular mass of solute.
Answer:
Relation between elevation in boiling point and molecular mass of solute:
Suppose, W_B gram of non – volatile solute dissolve in WA gram of solvent and the molecular mass of non – volatile solute is M_B gram. Then, molality, m will be

Question 8.
What is van’t Hoff factor? How does it equation?
Answer:
van’t Hoff Equation : van’t Hoff equation

Question 9.
What are constant boiling mixture? Write three differences in Ideal solution and Non – ideal Solutions. (MP 2011,15,16)
Answer:
Constant boiling mixtures or azeotropic mixture. A Solution which distils with out change in composition is called azeotropic mixture.
Differences between Ideal and Non – ideal Solution:

Question 10.
Define the following :

1. Reverse osmosis
2. Isotonic Solution
3. Semi – permeable membrane.

Answer:
1. Reverse osmosis:
It may be noted that if a pressure higher than the osmotic pressure is applied on the Solution the solvent will flow from the Solution into the pure solvent through the SPM. The process is called reverse osmosis.

2. Isotonic Solutions:
The Solution:s which have same osmotic pressure are called as isotonic Solution:s. For example, 0.91% Solution of NaCl called as saline water is isotonic with human blood corpuscles. That is why medicines are mixed with saline water before intravenous injections.

Osmotic pressure is a colligative property and depends on the number of solute particles in a Solution So, the isotonic Solution:s must have same number of solute particles in a given volume of Solution Consequently, the isotonic Solution:s are those which have same molality, if that the solute neither associate nor dissociate in the Solution.

3. Semipermeable membrane:
These are the membrane which allow the movement of the solvent molecules through them. The membrane appear to be continuous sheets or films. But they have very tiny holes or pores which are semimicro in nature. Through the holes, only the molecules of solvent can pass while those of bigger solute molecules cannot pass through.

Solutions Long Answer Type Questions

Question 1.
Write five differences in Solution: having Positive deviation and Negative deviation.
Answer:
Differences between Positive deviation and Negative deviation :

Question 2.
Explain in brief Berkeley and Hartley’s method of osmotic pressure measurement and state its uses.
Answer:
Berkeley and Hartley’s method:
In this method, pressure is applied over the Solution to stop the flow of solvent. This pressure is equivalent to osmotic pressure.
In this method, the apparatus consists of a strong vessel made up of steel in which porous pot is fitted. In the porous pot, copper ferrocyanide semipermeable membrane is deposited. The porous pot is fitted with a capillary tube on one side and a water reservoir on the other side. A piston and pressure gauge are fitted to the steel vessel.

The porous pot and steel vessel are filled with water and Solution respectively. Osmosis takes place and water moves into the steel vessel from the porous pot through the semipermeable membrane. This is shown by fall in water level in the capillary tube. This flow of water is stopped by applying external pressure on the Solution with the help of piston.

This method has the following advantages :

1. It takes comparatively lesser time to determine osmotic pressure.
2. Concentration of Solution: does not change, hence better results are obtained.
3. As high pressure is not exerted over semipermeable membrane, it does not break.
4. High osmotic pressure can be measured.

Question 3.
What is molal freezing point depression constant? Derive the formula to establish relation between molal freezing point depression constant and molecular mass of solute.
Or,
What is molal freezing point depression constant? Show that depression in freezing point is a colligative property. How can molecular mass of solute be determined from depression in freezing point?
Answer:
Molal freezing point depression constant is equal to depression in freezing point of the Solution when 1 gm mole is dissolved in 1000 gm of solvent. It is represented by i.e.,
K_f = \(\frac {depression in freezing point}{Number of moles}\)
or ∆ T_f = K_f x m
As K_f is molal freezing point depression constant, then
∆ T_f ∝m
Where, m = Number of moles dissolved in 1000 gm solvent.
Thus, depression in freezing point is proportional to molality of Solution. Molality is directly proportional to number or molecules of solute substance. Therefore, depression in freezing point is a colligative property.
Calculation of molecular mass of solute:
By determination of depression in freezing point, the Molecular mass of non – volatile solute can be determined.
For a Solution: of non – volatile solute,
∆T_f = K_f x m .. (1)
Let WB gram non – volatile solute is dissolved in w_A gram solvent and molecular mass of solute is M_B.

Question 4.
What is elevation in boiling points? How addition of a non – volatile solute elevates the boiling point of a solvent? Explain it with the help of graph diagram.
Answer:
The vapour pressure of the Solution:
containing a non – volatile solute is always less than that of pure solvent. Therefore, the Solution has to be heated to higher temperature so that its vapour pressure become equal to the atmospheric pressure. Thus, the boiling point of Solution (T_b)is always higher than the boiling point of solvent (T_b⁰). The difference T_b – T_b⁰ is called elevation in boiling point.

If we plot graph between temperature and vapour pressure of a pure solvent and its Solution, then following curve is obtained. Curve AB gives the vapour pressure for the pure solvent and the curve CD gives the vapour pressure of the Solution: at different temperature. At temperature T_b⁰ the vapour pressure of the solvent becomes equal to the atmospheric pressure hence it boils at T_b⁰.

Now, by the addition of non – volatile solute, lowering of vapour pressure of the Solution takes place. And to increase the vapour pressure of the Solution to become equal to atmospheric pressure, the temperature rises. Hence, at T_b the Solution boils. Thus, the boiling point is now elevated from T_b⁰ to T_b. The rise in temperature that results by the addition of a non – volatile solute in a solvent is termed as elevation in boiling point. It is represented by ∆T_b.
So, elevation in boiling point (∆T_b) = T_b – T_b⁰.

Question 5.
What are Non – Ideal Solution? How many types of are they? Explain with giving examples.
Answer:
Non – ideal Solutions:
Solutions in which Raoult’s law cannot be applied completely for all concentrations and temperatures are called non – ideal Solutions.
For these Solutions:

1. P_A ≠ P⁰_A X_A and p_B ≠ P⁰_BX_B,
2. ∆V_mixmg ≠ 0 and
3. ∆H_mixmg ≠ 0 and

Non – ideal Solution are of two types :

1. Solutions showing positive deviations:
For such Solutions the total vapour pressure will be greater than the corresponding vapour pressure according to the Raoult’s law. The boiling point of such Solutions are lowered. Because interactions between the mol-ecules of Solution: is less than the interactions between pure solvents and solutes. Thus the vapour pressure greater than expected. In these type of Solution formed enthalpy and volume increases.
Characteristics:

• P_A > P⁰_A X_A and P_B > P⁰_B X_B
• ∆V_mixlng > 0
• ∆H_mixlng > 0

Example:
Solution of Cyclohexane and Ethanol:
In Ethanol, its molecules are held together by hydrogen bond

On adding cyclohexane, the molecules tend to occupy the space between ethyl alcohol molecules. As a result the attractive forces between alcohol molecules becomes less. Thus, formation of such Solution: is slight increase in vapour pressure, endothermic and an increase in volume.

2. Solutions showing negative deviations:
For such Solutions the total vapour pressure becomes less than expected according to the Raoult’s law. Because interaction between molecules of Solution is greater than interaction between the pure solvent or solute molecules. Thus the vapour pressure of Solution is less. In these type of Solutions formed enthalpy and volume decreases.
Characteristics:

• P_A < P⁰_A X_A and P_B < P⁰_B X_B
• ∆V_mixlng < 0
• ∆H_mixlng < 0

Example:
Solution of Acetone and Chloroform:
When acetone and chloroform are mixed, there are new attractive forces due to intermolecular hydrogen bonding. These force become stronger. Thus the formation of such Solution:s is an exothermic and the vapour pressure of Solution is less and decrease in volume.

Solutions Numerical Questions

Question 1.
Calculate the mass of urea (NH₂ CONH₂ ) required in making 2.5 kg of 0.25 molal aqueous Solution. (NCERT)
Solution:
0.25 molal aqueous Solution means that
Moles of urea = 0.25 mole
Mass of solvent (water) = 1 kg = 1000 g
Molar mass of urea = 14+ 2 +12+ 16 +14+ 2 = 60 g mol^-1
∴ 0 .25 mole of urea = 60 x 0.25 mole = 15 g
Total mass of the Solution = 1000 + 15 g
= 1015 g = 1.015 g
∵ 1.015 kg of Solution contain urea = 15 g
∴ 2.5 kg of Solution will require urea = \(\frac {1.5}{1.015}\) x 2.5 kg = 37 g.

Question 2.
Henry’s law constant for CO₂ in water is 1.67 x 10⁸ Pa at 298 K. Calculate the quantity of CO₂ in 500 ml of soda water when packed under 2.5 atm CO₂ pressure at 298 K. (NCERT)
Solution:
According to Henry’s law,
P = K_HX .. (1)
P = 2.5 atm = 2.5 x 101325 Pa, KH= 1.67 x 10⁸ Pa
Putting these values in equation (1), we get

Question 3.
Calculate the mass of ascorbic acid (Vitamin C, C₆H₈O₆) to be dissolved in 75 g of acetic acid to lower its melting point by 1.5°C. K_fK kg mol^-1. (NCERT)
Solution:
We know that ∆T_f = K_f x \(\frac{\mathrm{W}_{\mathrm{B}} \times 1000}{\mathrm{M}_{\mathrm{B}} \times \mathrm{W}_{\mathrm{A}}}\) .. (1)
Given ∆T_f = 1.5, K_f = 3.9 K kg mol^-1, W_A = 75g, MB (ascorbic acid, C₆H₈O6)
= 6 x 12 + 8 x l + 16 x 6 = 176
Putting, these values in equation (1),
1.5 = 3.9 x \(\frac{\mathrm{W}_{\mathrm{B}} \times 1000}{176 \times 75}\)
W_B = 5.077g.

Question 4.
Calculate the osmotic pressure in pascals exerted by a Solution prepared by dissolving 1.0 g of polymer of molar mass 1,85,000 in 450 ml of water at 37°C. (NCERT)
Solution:
π = CRT
= \(\frac {n}{V}\) RT
Here, number of moles of solute dissolved (n)
= \(\frac {1.0}{185,000}\) mol^-1
= \(\frac {1}{185,000}\) g mol^-1
v = 450mL = 0.450 L
T = 37°C = 37 + 273 = 310 K
R = 8.314 K Pa LK^-1 mol^-1
= 8.314 x 103 Pa LK^-1 mol^-1
Substituting these values we get,

Question 5.
Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in aqueous Solution. What should be the molarity of such a sample of the acid if the density of the Solution is 1.504 g ml^-1? (NCERT)
Solution:
68% nitric acid by mass means that
Mass of nitric acid = 68 g
Mass of Solution = 100 g
Molar mass of HNO₃ = 63 g mol^-1
∴ 68 g HNO₃ = \(\frac {68}{63}\) mole = 1.079 mole
Density of solution = 1.504 g mL^-1
∴ Volume of solution = \(\frac {100}{1.504}\)mL = 66.5 mL = 0 0665 L
Molarity of the solution = \(\frac {Moles of the solute}{Volume of Solution in L}\)
= \(\frac {1.079}{0.0665}\) M = 16.23 M.

Question 6.
Vapour pressure of water at 293 K is 17.535 mm Hg. Calculate the vapour pressure of water at 293K when 25g of glucose is dissolved in 450g of water. (NCERT)
Solution:
\(\frac { { p }^{ 0 }-{ p }^{ 0 } }{ { p }^{ 0 } } \) = X₂ = \(\frac { { W }_{ B }{ M }_{ A } }{ { M }_{ B }{ W }_{ A } } \)
or \(\frac { 17.535-{ P }_{ s } }{ 17.535 }\) = \(\frac { 25×18 }{ 180×450 }\)
or \(\frac { 17.535-{ P }_{ s } }{ 17.535 }\) = 5.56×10^-3
17.535 – p_s = 0.0975
P_s = 17.438 mm Hg.

Question 7.
Henry’s law constant for the molality of methane in benzene at 298 K is 4.27 x 10⁵mm Hg. Calculate the solubility of methane in benzene at 298K under 760 mm Hg. (NCERT)
Solution:
Here, KH = 4.27 x 10⁵ mm, P = 760 mm
Applying Hemy’s law, P = K_HX
\(\mathrm{X}=\frac{\mathrm{P}}{\mathrm{K}_{\mathrm{H}}}=\frac{760}{4 \cdot 27 \times 10^{5}}\) =1.78 x 10^-3
∴ Mole fraction of methane in benzene = 1.78 x 10^-3

Question 8.
Benzene and toluene form ideal solution over the entire range of composition. The vapour pressure of pure benzene and toluene at 300K are 50.71 mm Hg and 32.06 mm Hg respectively. Calculate the mole fraction of benzene in vapour phase if 80 g of benzene is mixed with 100 g of toluene. (NCERT)
Solution:
A → Benzene (C₆H₆); B —> Toluene (C₇H₈)
Number of moles of benzene n_A = \(\frac {80}{78}\)
Number of moles of toluene = n_B = \(\frac {100}{92}\)
X_A = \(\frac { { n }_{ A } }{ { n }_{ A }+{ n }_{ B } } \quad\) = \(\frac {1.026}{1.026+1.087}\) = 0.486
X_B = 1 – X_A = 1 – 0.486 = 0.514
Given P°_A = 50.71 mm Hg and P°_B = 32.06 mm Hg
We know, P = P_A + P_B
= P°_AX_A + P°_AX_B
= (50.71 x 0.486) + (32.06 x 0.514)
= 24.65+ 16.48 = 41-13
Mole fraction of components in vapour phase may be calculated by using Dalton’s law,
P_A = y_A x P
y_A = \(\frac { { P }_{ A } }{ p } \quad \) = \(\frac {24.65}{41.13}\) = 0.60

Question 9.
Determine the osmotic pressure of 5% glucose Solution at 25°C. Molecular mass of glucose = 180, R = 0.0821 litre atmosphere. (MP 2013,16)
Solution:
∴5 gm glucose is dissolved in 100 ml.
∴ 180 gm glucose will be dissolved in \(\frac {100}{5}\) x 180
= 3600 ml = 3.6 litre.
We know that,
PV = RT
P x 3.6 = 0.0821 x (25 + 273) = 298
or P = \(\frac {0.52×12.5×1000}{0.63×170}\)
= 6.80 atmospheres.

Question 10.
12.5 gm of urea dissolved in 170 gm of water. The elevation in boiling point was found to be 0.63 K. If KA for water = 0.52 Km^–1, calculate the molecular mass of urea. (MP 2010)
Solution:
Formula: M_B\(\frac { { K }_{ b }x{ W }_{ B }x1000 }{ ∆{ T }_{ b }x{ W }_{ A } }\)
Given: W_A = 170gm,W_B= 12.5gm, ∆T_B=0.63K, K_b=0.52Km^-1
M_B = \(\frac {0.52×12.5×1000}{0.63×170}\)
M_B = 60.7 gm mol^-1

Question 11.
If 6.84 gram sucrose is dissolved in 100 ml. Solution then what will be its osmotic pressure at 20°C? (R = 0.082 litre atmosphere K^-1mol^-1) (Molecular mass of sucrose M_B = 342)
Solution:
Given : Weight of solute (W_B) = 6.84 gm
Molecular mass of solute (M_B) = 342
Volume of Solution: (V) =\(\frac {100}{1000}\) =0.1 litre
Temperature (T) = 20° C = 273 + 20 = 293 K
Solution constant R = 0.082 litre atmosphere K^-1 mol^-1
Osmotic pressure π = \(\frac { { W }_{ B }RT }{ { M }_{ B }V } \)
= \(\frac {6.84×0.082×293}{342×0.1}\)
= 4.8 atmosphere.

MP Board Class 12th Chemistry Important Questions

MP Board Class 11th Chemistry Important Questions Chapter 7 Equilibrium

Equilibrium Important Questions

Equilibrium Objective Type Questions

Question 1.
Choose the correct answer:

Question 1.
Which of the following reaction have equal K_c and K_p:
(a) N_2(g) + 3H_2(g) ⇄ 2NH₃
(b) 2H₂S_(g) + 3O_2(g) ⇄ 2SO_2(g) + 2H₂O_(g)
(c) Br₂ + Cl_2(g) ⇄ 2BrCl_(g)
(d) P_4(g) + 6Cl_2(g) ⇄ 4PCl_3(g)
Answer:
(c) Br₂ + Cl_2(g) ⇄ 2BrCl_(g)

Question 2.
For the reaction N_2(g) + 3H_2(g) ⇄ 2NH_3(g), ∆H = 92 kJ, the concentration of NH₃ at the equilibrium increase by temperature:
(a) Increase
(b) No change
(c) Decrease
(d) None of the above
Answer:
(c) Decrease

Question 3.
In one litre container equilibrium mixture of reaction 2H₂S_(g) ⇄ 2H₂S_(g) + S₂S_(g) is filled 6.5 mol H₂S. 0.1 mol H₂ and 0.4 mol S₂ are present in it. Equilibrium constant of this reaction will be:
(a) 0.004 mol litre^-1
(b) 0.080 mol litre^-1
(c) 0.016 mol litre^-1
(d) 0.160 mol litre^-1
Answer:
(c) 0.016 mol litre^-1

Question 4.
Favourable condition for exothermic reaction of ammonia synthesis N₂S_(g) + 3H₂S_(g) ⇄ 2NH_3(g) are:
(a) High temperature and high pressure
(b) High temperature and low pressure
(c) Low temperature and high pressure
(d) Low temperature and pressure
Answer:
(c) Low temperature and high pressure

Question 5.
Oxidation of SO₂ by O₂ in SO₃ is an exothermic reaction manufacture of SO₃ will be maximum if:
(a) Temperature increased and pressure decreased
(b) Temperature decreased and pressure increased
(c) Temperature and pressure both increased
(d) Temperature and pressure both decreased.
Answer:
(b) Temperature decreased and pressure increased

Question 6.
At 440°C HI was heated in a closed vessel till equilibrium is attained. It is dissociated 22%. Equilibrium constant dissociation will be:
(a) 0.282
(b) 0.0796
(c) 6.0199
(d) 1.99
Answer:
(c) 6.0199

Question 7.
K_p and K_c can be expressed as:
(a) K_c = Kp (RT)^∆n
(b) K_p = K_c (RT)Q^∆n
(c) K_p = K_c(RT)^∆n
(d) K_c = K_p (RT)^∆n
Answer:
(c) K_p = K_c(RT)^∆n

Question 8.
The equilibrium constant of the reaction H_2(g) + I_2(g) ⇄ 2HI_2(g), is 64. If the volume of the container is reduced to one – fourth of its original volume. The value of the equilibrium constant will be:
(a) 16
(b) 32
(c) 64
(d) 128
Answer:
(c) 64

Question 9.
What would happen to a reversible reaction at equilibrium when an inert gas is added while the presence remain unchanged:
(a) More of the product will be formed
(b) Less of the product will be formed
(c) More of the reactant will be formed
(d) It remains unchanged
Answer:
(d) It remains unchanged.

Question 10.
SO_2(g) + \(\frac{1}{2}\) O_2(g) ⇄ SO_3(g), K₁
2SO_3(g) ⇄ 2SO_2(g) + O_2(g), K₂ which of the following is correct:
(a) K₂ = K₁²
(b) K₂ = K₁^-2
(C) K₂ = K₁
(d) K₂ = K₁^-1
Answer:
(b) K₂ = K₁^-2

Question 11.
Which reaction is not affected by change in pressure:
(a) N_2(g) + O_2(g) ⇄ 2NO_(g)
(b) 2O_3(g) ⇄ 3O_2(g)
(c) 2NO_2(g) ⇄ N₂O_4(g)
(d) 2SO_2(g) + O_2(g) ⇄ 2SO_3(g)
Answer:
(a) N_2(g) + O_2(g) ⇄ 2NO_(g)

Question 12.
For N₂ + 3H₂ ⇄ 2NH₃ + heat:
(a) K_p = K_c
(b) K_p = K_cRT
(c) K_p = K_c (RT)^-2
(d) K_p = K_c(RT)^-1
Answer:
(c) K_p = K_c (RT)^-2

Question 13.
Sodium sulphate dissolve in water with the release of heat. Imagine a saturated solution of sodium sulphate. If temperature is increased then according to Le – Chatelier principle:
(a) Mass of solid will be dissolved
(b) Some solid will be precipitated in solution
(c) Solution will be more saturated
(d) Concentration of solution will be unchangeble.
Answer:
(b) Some solid will be precipitated in solution

Question 14.
For reaction, PCl_3(g) + Cl_2(g) ⇄ PCl_5(g) value of K_c at 250° is 26 value of K_p at this temperature will be:
(a) 0.61
(b) 0.57
(c) 0.83
(d) 0.46
Answer:
(a) 0.61

Question 15.
According to Le – Chatelier principle when heat is given on solid – liquid equilibrium then:
(a) Amount of solid decreases
(b) Amount of liquid decreases
(c) Temperature increases
(d) Temperature decreases
Answer:
(a) Amount of solid decreases

Question 2.
Fill in the blanks:

1. For an endothermic process, PCl₅ ⇄ PCl₃+ Cl₂; ∆H = + Q cal. Hence, in this reaction, temperature should be kept ………………………. and pressure ………………………. (If reaction is to be carried out in forward direction)
2. Ice ⇄ Water – Q cal. High temperature in this reaction favours …………………………. direction while increase in pressure favour reaction in ………………………… direction.
3. According to Ostwald’s dilution law, mathematical relation between degree of dissociation and dissociation constant is expressed by ……………………….. Degree of dissociation of weak electrolyte is inversely proportional to its …………………………..
4. Relation between solubility and solubility product for the reaction AB ⇄ A⁺ + B^– is expressed as ……………………….
5. For the maximum yield of SO₃ in the reaction 2SO₂ + O₂ → 2SO₃, ……………………… temperature and pressure is required.
6. Mixture of acetic acid and sodium acetate is an example of ……………………….. solution
7. Mixture of ammonium hydroxide and ammonium chloride is an example of ……………………… solution
8. Degree of dissociation of a weak electrolyte is inversely proportional to ………………………… of concentration.
9. Ostwald dilution law is not applicable for ……………………..
10. Heneiy’s law is related to solubility of in …………………………. solution
11. Relation between K_p and K_c at constant temperature for reaction is ………………………

Answer:

1. High, low
2. Forward, forward
3. α = \(\sqrt { \frac { K }{ C } } \), square root of concentration
4. K_sp = [A⁺] [B^–]
5. Low temperature, high pressure
6. Acidic buffer
7. Basic buffer
8. Square root
9. Strong electrolyte
10. Gas
11. K_p = K_c × RT^∆n.

Question 3.
Answer in one word/sentence:

1. What is the value of K_p and K_c for the given reaction:
   • PCl₅ ⇄ PCl₃ + Cl₂
   • H₂ + I₂ ⇄ 2HI
2. For the unit of K_c, concentration is expressed in?
3. Manufacture of nitrogen peroxide is exothermic. What should be temperature and pressure for maximum yield?
4. Ammonia gas dissolves in water giving NH₄OH. How is water reacting in it?
5. When NH₄Cl is added to NH₄OH solution, dissociation of NH₄OH decreases, why?
6. pH of water at 298K?
7. What is hydrogen ion concentration in pure water?
8. pH of water at 25°C is 7. If water is heated to 50°C, what change in its pH will occur?
9. Write conjugate base of H₂PO₄^– and HCO₃^–?
10. Name one ion which behaves as both Bronsted acid and base?

Answer:

1. • K_p > K_c
   • K_p = K_c
2. mol/litre
3. Low temperature and high pressure
4. Like acid
5. Common ion effect
6. 7
7. 1 × 10^-7
8. pH value decreases,
9. HPO₄^2- CO₃^2-
10. HCO₃^–

Question 4.
Match the following:
[I]

Answer:

1. (d)
2. (e)
3. (b)
4. (a)
5. (c)
6. (f)

[II]

Answer:

1. (d)
2. (c)
3. (a)
4. (e)
5. (b)

Equilibrium Very Short Answer Type Questions

Question 1.
For unit of Kc the concentration is expressed as?
Answer:
mol/litre.

Question 2.
Ammonia when dissolve in water give NH₄OH, here the water acts as?
Answer:
Like acid.

Question 3.
When NH₄Cl is mixed with NH₄OH solution, then the ionisation of NH₄OH decreases. What is the reason?
Answer:
Due to Common ion effect.

Question 4.
The pH of water at 25°C pH = 7. If water is heated upto 50°C, then what will be the change in pH?
Answer:
The value of pH decreases.

Question 5.
Write the conjugate base of H₂PO₄^– and HC0₃^–?
Answer:
HPO₄^2- and CO₃^2-.

Question 6.
Write the name of an ion which acts as both Bronsted acid and base?
Answer:
HCO₃^–.

Question 7.
Give an example of a salt formed by weak acid and weak base?
Answer:
Ammonium acetate.

Question 8.
What is the pH value of human blood?
Answer:
7.4.

Question 9.
What will happen when HCl gas is passed through NaCl?
Answer:
NaCl will precipitate.

Question 10.
Among conjugate bases CN^– and F^–, which is stronger base?
Answer:
CN^– is stronger base.

Question 11.
What is the change in free energy (∆G) of reversible process at equilibrium?
Answer:
Zero (0).

Question 12.
What is solubility product?
Answer:
The product of the concentration of ions in the saturated solution of a sparingly soluble salt is a constant at a given temperature and is called solubility’ product.

Question 13.
What is buffer solution?
Answer:
The solution in which on adding acid or base in iess quantity, the pH change is negligible, is called buffer solution.

Question 14.
In the exothermic reaction of ammonia formation N_2(g) + 3H_2(g) ⇄ 2NH_3(g), when be the formation of ammonia will be more?
Answer:
At low temperature and high pressure the formation of anunorua is more.

Question 15.
Give an example of acidic buffer?
Answer:
Mixture of acetic acid and sodium acetate.

Question 16.
What is the condition for precipitation?
Answer:
For this ionic product should he more than solubility product.

Question 17.
What is the nature of aqueous solution of KCN?
Answer:
It is of basic nature.

Question 18.
What is the nature of aqueous solution of CH₃COONH₄?
Answer:
It is of neutral nature.

Question 19.
What will be the relation between K_c and K_p for the reaction
PCl₅ ⇄ PCl₃ + Cl₂
Answer:
K_p > K_c.

Question 20.
What is Lewis concept?
Answer:
Acid is an electron pair acceptor and base is an electron pair donor.

Question 21.
What is the definition of acid and base according to Bronsted and Lowry concept?
Answer:
Acid is that which furnishes proton and base accepts the proton.

Question 22.
What is pH?
Answer:
The pH value of a solution is the numerical value of the negative power to which 10 should be raised in order to express the Hydrogen ion concentration of the solution i.e. [H⁺] = 10^-pH or pH = – log [H⁺].

Question 23.
The Ostwald dilution law applied on which electrolyte?
Answer:
On weak electrolytes.

Equilibrium Short Answer Type Questions – I

Question 1.
Explain the effects of catalyst at equilibrium?
Answer:
Effect of catalyst:
Le – Chatelier’s principle ignores the presence of a catalyst since the catalyst cannot displaces the equilibrium and simply reduce the time required for attaining the equilibrium when a catalyst is added to a reversible reaction in equilibrium. (MPBoardSolutions.com) It increases the speed of both forward and backward reaction i.e. r_f and r_b to the same extent. However the addition of a catalyst reduces the time required for a reaction to attain the equilibrium.

Question 2.
Explain Ostwald’s law of dilution?
Answer:
Ostwald’s time dilution law:
Ostwald gave law for weak elecrolytes. By applying law of mass action Ostwald gave a law for expressing the dissociation of weak electrolyte. It states that:
“The degree of dissociation of weak electrolyte is directly proportional to the square root of its dilution.”
α = \(\sqrt { KV } \) = \(\sqrt { \frac { K }{ C } } \)
Where, α = Degree of dissociation, K = Dissociation constant, V = Volume in litre in which one gram equivalent is dissolved, C = No. of gram equivalent in one litre.

Question 3.
What is the effect of pressure on chemical equilibrium?
Answer:
On increasing the pressure on chemical equilibrium, the equilibrium shifts in that direction where the volume decreases i.e., the number of moles decreases.
Example: On combining of SO₂ and O₂, SO₃ is formed and 45.2 kcal energy is liberated.
2SO_2(g) + O_2(g) ⇄ 2SO_3(g); ∆H = -45.2 kcal
In this reaction, 2 moles of SO₂ react with 1 mole of O₂ to form 2 moles of SO₃. So, on increasing the pressure the reaction shifts toward forward direction.

Question 4.
What do you mean by buffer solution?
Answer:
Buffer solution: Solution in which,

1. pH value is definite.
2. pH is not changed on dilution or on keeping for sometime.
3. On adding acid or base in less quantity, pH change is negligible.

Such solutions are called buffer solutions.
Or
Buffer solutions are solutions which retain their pH constant or unaltered.

Question 5.
What are acidic buffer and basic buffer?
Answer:
1. Acidic buffers:
Acidic buffers are formed by mixing an equimolar quantities of weak acid and its salt with a strong base.
Example: Acetic acid and sodium acetate, boric acid and borax, citric acid and so-dium citrate, etc.

2. Basic buffers:
Basic buffers contain equimolar quantities of weak base and its salt with strong acid.
Example: Ammonium hydroxide and ammonium chloride.

Question 6.
On the basis ofthe equation pH = – log[H⁺], the pH of the 10^-8mol dm^-3 HCl solution should be pH = 8. But the observed value is less than 7. Explain the reason?
Answer:
The 10^-8moldm^-3HCl shows that the solution is very dilute. So, we cannot neglect the H₃O⁺ ions formed from water in the solution. So, the total [H₃O⁺ ] = (10 ^-8 + 10^-7) M comes to be near 7 or less than 7 i.e., the pH is less than 7. (As the solution is acidic).

Question 7.
Ammonia is a Lewis base. Why?
Answer:
According to Lewis base, a base, is a substance (molecule or ion) which can donate an electron pair to form a co – ordinate. In the structure of ammonia, nitrogen is present in one lone pair of electron. So, ammonia donate a lone pair electron.
For example:

Question 8.
Write the uses of Buffer solution?
Answer:
Uses of Buffer solution:

1. To keep the pH of the reaction constant during the determination of velocity of chemical reactions.
2. The pH should be between pH – 5 to 6 – 8 in the formation of alcohol by fermentation.
3. Preparation of sugar, paper and electroplating occurs at definite pH.

Question 9.
What is the effect of pressure and temperature on solubility of gases in liquids?
Answer:
1. Effect of Pressure:
On increasing the pressure the solubility of gases increases as the molecules of gases enters in the intermoiecular spaces of solvent.

2. Effect of Temperature:
On increasing the temperature the solubility of gases decreases as the kinetic energy of gas molecules increases.

Question 10.
Write the name of the factors affecting the chemical equilibrium?
Answer:
The factors affecting the chemical equilibrium are:

1. Temperature
2. Pressure
3. Change in concentration
4. Catalyst.

Question 11.
Why the solubility of C0₂ decreases on Increasing the temperature?
Answer:
CO_2(g) + aq ⇄ CO_2(eq)
The solubility of CO₂ in water is an exothermic reaction. So, according to Le – Chatelier’s principle, on increasing temperature the reaction proceeds towards backward direction. That is why on increasing temperature the solubility of CO₂ decreases.

Question 12.
What do you understand by ionization of water?
Answer:
Auto ionisation occurs in water molecules. The ionic equilibrium of water can be shown by following equation:
H₂O + H₂O ⇄ H₃OH⁺ + OH^–
Equilibrium constant K = \(\frac { [H_{ 3 }O^{ + }][OH^{ – }] }{ [H_{ 2 }O]^{ 2 } } \)
⇒ K_H2O = [H₃O⁺][OH^–] [∵ K_H2O = K_w]
K_w = 1 × 10^-14
Here K_w is a constant, called ionic product of water.

Question 13.
What is concentration Quotient?
Answer:
The ratio of concentration of products and reactants is called concentration quotient. It is denoted by Q. For any reversible reaction the concentration quotient is equal to the equilibrium constant K_c.
K_c = \(\frac { [C]^{ c }[D]^{ d } }{ [A]^{ d }[B]^{ b } } \)
and Q = \(\frac { [C_{ C }]^{ c }[C_{ D }]^{ d } }{ [C_{ A }]^{ d }[C_{ B }]^{ b } } \)
At equilibrium Q = K_c.

Question 14.
What do you understand by Lewis acid and Lewis base? Explain with example?
Answer:
Lewis acid:
Acid is a substance (an atom, molecule or ion) which can accept a pair of electrons to complete its octet.
Example: BF₃, AlCl₃, Br⁺, NO₂⁺ etc.

Lewis base:
Lewis base is a substance (an atom, molecule or ion) which have complete octet of the central metal atom and have a lone pair of electron to donate in a chemical reaction to form co – ordinate bond.
Example:

Question 15.
At 310 K, ionic product of water is 2.7 × 10^-14. at this temperature determine the pH of neutral water?
Solution:
K_w = [H₃O⁺].[OH^–] = 2.7 × 10^-14 (At 310 K)
For reaction H₂O + H₂O ⇄ [H₃O⁺] [OH^–]
[H₃O⁺] = [OH^–]
So, [H₃O⁺] = \(\sqrt { 2.7\times 10^{ -14 } } \) = 1.643 × 10^-7M
∴_pH = -log [H₃O⁺] = -log 1.643 × 10^-7
= 7 + (- 0.2156) = 6.7844.

Question 16.
Determine the concentration quotient for following reactions:

1. CrO₄^-2_(eq) + Pb_(eq) ⇄ PbCrO_4(s)
   
2. CaC0_3(s) ⇄ CaO_(s) + CO_2(g)
   
3. NH_3(eq) + H₂O_(l) ⇄ NH₄⁺_(eq) + OH^–_(eq)
4. H₂O_(l) ⇄ H₂O_(g)

Answer:

Question 17.
What is the importance of solubility product in precipitation of soap?
Answer:
Soap is produced on alkaline hydrolysis of oil and fats. Soaps are actually sodium or potassium salts of higher fatty acids. (MPBoardSolutions.com) Soap is obtained in the form of concentrated liquid. Concentrated salt solution is added for its precipitation. In presence of increased concentration of common sodium ion, ionic product of [Na⁺] [C_n H_2n+1 COO] exceeds its solubility product (K_sp) and it gets precipitated. It is separated by filtration.

Equilibrium Short Answer Type Questions – II

Question 1.
By comparing the values of Kc and how will you find out the following state of the reaction:

1. Resultant reaction proceeds towards forward direction.
2. Resultant reaction proceeds towards backward direction.
3. No change in the reaction.

Answer:

1. If Q_c < K_c; reaction proceeds towards the direction by products (Forward reaction).
2. If Q_c > K_c; reaction proceeds towards reactant side (Backward reaction).
3. If Q_c = K_c; at equilibrium, the reaction mixture remains as before. So no change in the reaction.

Question 2.
The aqueous solution of sodium carbonate is basic in nature, why?
Answer:
Na₂CO₃ ⇄ 2Na⁺ + CO₃^-2
2H – OH ⇄ = 2H⁺ + 2OH^–
Na₂CO₃ + 2H – OH ⇄ 2NaOH + H₂CO₃
Neither solid Na₂CO₃ nor water alone has any action on litmus paper. However aqueous solution of Na₂CO₃ turned red litmus blue. The problem is successfully explained by the Arrhenius theory of ionization in terms of hydrolysis, when a salt is dissolved in water, it undergoes ionization. (MPBoardSolutions.com) The ions of salt interact with opposite ion of water to form acidic basic or neutral solution. This process is called hydrolysis may be defined as the interaction of ion of a salt with oppositely charged ion of water to give acidic or basic solution. Consider the hydrolysis of a general salt (AB).
Dissociation of salt
AB +Water → A⁺ + B^–
Dissociation of water

Question 3.
What is the effect on equilibrium when gases are dissolved in liquids? Explain with example?
Answer:
When the soda water bottle is opened, dissolved CO₂ gas in it comes out rapidly. This is an example of equilibrium of any gas in equilibrium between gas and its liquid. At finite pressure of the gas there exists an equilibrium between soluble and insoluble molecules of the gas.
CO_2(g) ⇄ CO_2(eq)
Henry’s law: The solubility of gas in a given solvent is directly proportional to the pressure to which the gas is subjected, provided the temperature remains the same.
Thus, m ∝ P
or m = KP
Where, K is a constant of proportionality and known as Henry’s constant.
Example: You have seen that when a soda water bottle is opened, the carbon dioxide dissolved in it freezes out rapidly. This can be explained on the basis of Henry’s law. (MPBoardSolutions.com) Carbonated beverages are bottled under pressure to ensure high concentration of carbon dioxide. When the bottle is opened the pressure above the solution falls and the excess carbon dioxide comes out.

Question 4.
What is common ion effect? Explain?
Answer:
Common ion effect:
When, in a solution of weak electrolyte, a solution of strong electrolyte containing the same ion is added, then the ionisation of weak electrolyte decreases. This effect is called common ion effect.
Example: During precipitation of radicals of group II taken care that the radicals of group IV does not get precipitated. (MPBoardSolutions.com) On the basis of this, H₂S gas is passed in presence of HCl in group II. Due to common ion effect dissociation of H₂S is suppressed.

This reduces concentration of sulphide ion and hence only radicals of group II get precipitated as sulphide. For the precipitation of radicals of group IV, H₂S is passed in presence of NH₄OH. H⁺ ion of H₂S combines with OH^– ions of NH₄OH to produce water. This increases dissociation of H₂S. In this way, increase in sulphide ion concentration helps in the precipitation of positive sulphides of group IV.

Question 5.
What do you understand by conjugate acid and conjugate base?
Answer:
The relative strengths of conjugate pairs can be found out, if we know whether forward reaction is favoured or backward reaction is favoured.
For example:

In the above reaction, the reaction proceeds almost to completion. We must therefore conclude that HCl is a stronger acid than H₃O⁺ i.e., HCl has stronger tendency to donate proton than H₃O⁺. Similarly H₂O is stronger base than H₂O has stronger tendency to accept proton than Cl^–. Thus, the strong acid (HCl) has a weak conjugate base Cl^–.
Consider another reaction

For the reaction, backward reaction is strongly favoured. This shows that H₃O⁺ is a stronger acid than CH₃COOH and CH₃COO^– is a stronger base than H₂O. Thus, we again observe that the strong acid (H₃O⁺) has the weak conjugate base (H₂O). Thus, we conclude that, A stronger acid has a weak conjugate base and vice – versa.

Question 6.
Explain the solubility product by giving definition?
Answer:
Solubility product:
The product of the concentration of ions in the saturated solution of a sparingly soluble salt as AgCl is a constant at a given temperature and is called solubility product. (MPBoardSolutions.com) If any sparingly soluble electrolyte at any temperature forms saturated solution, then the equilibrium is

According to law of mass action from (b) and (c),
\(\frac { [A^{ + }][B^{ + }] }{ [AB] } \) = K
∴ [A⁺ ][B⁺ ] = K[AB]
When solution is saturated [AB] will be constant and value of K[AB] will also be a constant and is written as KJ which is the solubility product.

Question 7.
Explain the acid – base concept of Bronsted – Lowry by giving example?
Answer:
Bronsted – Lowry concept of acid and base (1923):
Scientist Bronsted and Lowry gave the theory for acids and bases which is equally applied to aqueous and non – aqueous solutions of acids and bases. According to it, “Acid is that which furnishes proton and base accepts the proton.”

Neutralization reaction:
A reaction in which a proton is transferred from acid to a base or a reaction between H⁺ and OH^– ion to form H₂O molecule.
Relation between acid and base:

That means, every acid has conjugate base and every base has conjugate acid.

According to the definition given by Bronsted and Lowry, acid and base may be in molecular, cationic or anionic states.

Question 8.
Calculate the value of equilibrium constant for following reaction:
PCl₅ ⇄ PCl₃ + Cl₂
Answer:
Let ‘a’ mole of PCl₅, initiate the reaction and x moles dissociate at equilibrium state. If the volume of container is V litre then,

According to law of mass of action
K_c = \(\frac { [PCl_{ 3 }][Cl_{ 2 }] }{ [PCl_{ 5 }] } \)
On putting the values,

Question 9.
With the help of Le – Chatelier’s principle at equilibrium for reaction 2SO₃ + O₂ ⇄ 2SO₃;
∆H = – 188.2 kJ, determine the restrictions for the formation of sulphur trioxide?
Answer:
Le – Chatelier proposed a law. It states “If as equilibrium m £ chemical system is disturbed by changing temperature, pressure or concentration of the system, the equilibrium shift is such a way so that the effect of change gets minimised.”
On the basis of this principle, changes in chemical equilibria and physical equilibria can be explained.
Formation of SO₃ by SO₂ and O₂:
2SO₂ + O₂ ⇄ 2SO₃; ∆H = – 45.2 kcal

1. Effect of concentration:
On increasing concentration of SO₂ and O₂ more SO₃ will be formed.

2. Effect of pressure:
On increasing pressure, the equilibrium shifts on that side in which number of moles are less or towards less volume. In this reaction, 2 moles of SO₂ and 1 mole of O₂ (Total 3 moies) change into 2 moles of SO₃, So, on increasing pressure, more quantity of SO₃ will be formed.

3. Effect of temperature:
Formation of SO₃ is an exothermic reaction, so on increasing temperature, more SO₃ will dissociate and on decreasing temperature, more SO₃ will be formed.

Question 10.
What is the importance of solubility product m the purifkation of salt?
Answer:
Purification of common salt; Common salt contains impurities in it. For removal of these HCl gas is passed through the saturated solution of salt. HCl ionizes tc greater extent being a strong electrolyte.
HCl ⇄ H⁺ + Cl^– (More ionized)
NaCl ⇄ NaCl ⇄ Na⁺ + Cl^–

Equilibrium Long Answer Type Questions – I

Question 1.
Explain the buffering action of alkaline or basic buffer? Give its importance?
Answer:
Bask buffer:
Basic buffer contains equimolar quantities of weak base and sodium citrate etc.
Buffer action of basic buffer: Consider a basic buffer of NH₄OH and NH₄Cl. This buffer solution contains a large amount of NH₄⁺ ions, Cl^– ions and excess of undissociated NH₄OH molecules along with a small amount of OH^– ions.
NH₄Cl → NH₄⁺ + Cl^–
NH₄OH ⇄ NH₄⁺ + OH^–
On adding a drop of HCl, H₃O⁺ ions produced combines with OH^– ions of the buffer to form weakly ionised H₂O molecules. As a result of this ionisation of NH₄OH increases to restore the concentration of OH^– ions. Sc, pH of solution remains unchanged.

When a few drops of NaOH is added, it provides OH^– ions. The additional OH^– ions combines with NH₄⁺ ions to form weakly ionised NH₄OH resulting an increase in ionisation of NH₄OH to restore the concentration of NH₄⁺ ion. Thus, pH remains unchanged.

Importance of Buffer solution:

1. Buffer solutions are very important in laboratories, industries, botanical or zoological, physiology. Human blood is an example of buffer solution which has pH 7.34.
2. In the extraction of phosphate the buffer solution of CH₃COONa and CH₃COOH is used.
3. In industries, for the manufacturing of sugar and paper and electroplating occurs at fixed pH.

Question 2.
What is pH? Explain?
Or, What is meant by pH? What is its relationship with hydrogen ion concentration?
Answer:
To express the acidity or basicity of a solution Sorensen in 1909 established a scale known as the pH scale.
The pH value of a solution is the numerical value of the negative power to which 10 should be raised in order to express the hydrogen ion concentration of the solution, i.e;
[H⁺] = 10^-pH …………… (1)
On taking log of eqn.(1),
or log₁₀[H⁺] = log₁₀ 10^-pH
log₁₀[H⁺] = -pH log₁₀ 10
or pH = -log [H⁺], (∵ log₁₀ 10 = 1)
or pH = log₁₀\(\frac { 1 }{ [H^{ + }] } \)
This is the required relationship between pH and H⁺ ion concentration.
Thus, the pH value of a solution is the logarithm of its hydrogen ion concentration to base 10 with negative sign.
pH scale expresses acidic and basic nature of solution in terms of numbers from 0 to 14. Acidic solutions have pH value less than 7 while basic solutions have pH value greater than 7. pH value of neutral solution is 7.
Uses of pH measurement:

1. In industries:
   • In the manufacturing of alcohol by fermentation, pH is maintained between 5 and 6.8.
   • Manufacturing of paper, sugar and electroplating is being done at fixed pH.
2. In the study of velocities of chemical reactions, for maintaining pH, buffer solutions are used.
3. In qualitative analysis for removal of phosphate to maintain pH, buffer solutions of CH₃COONa and CH₃COOH are used.
4. pH of human blood is 7.34. Medium of stomach is acidic while in the intestine it is basic medium.

Question 3.
Write the characteristics of equilibrium constant?
Answer:
Characteristics of equilibrium constant:
1. The value of equilibrium constant for a reaction is constant at a given temperature and it changes with change in temperature.

2. The value of molar equilibrium constant does not depends upon the initial molar concentration of reactants and products but it depends upon their concentration at equilibrium state.

3. If the reaction is reversed the value of equilibrium constant is inversed. For example,
Then for, H_2(g) + I_2(g) ⇄ 2HI, K_c = 50
2HI_(g) ⇄ H_2(g) + I_2(g)
∴ K’ = \(\frac { 1 }{ K } \) or K’_c = \(\frac{1}{50}\) = 0.02

4. If the equation having equilibrium constant is divided by 2, the equilibrium constant for the new equation is the square root of K (i.e., \(\sqrt { K } \))
For example:

5. If the equation (Having equilibrium constant K) is multiplied by 2, the equilibrium constant for the new equation is square of K (i. e., K²)
K’ = K²

Question 4.
Give only the definition of:

1. Salt hydrolysis
2. Solubility product
3. Common ion effect
4. Buffer solution

Answer:
1. Salt hydrolysis:
The interaction of cation/anion or both with water making the solution acidic or basic is called salt hydrolysis.

2. Solubility product:
At a particular temperature the product of concentration of ions in a saturated solution of a sparingly soluble electrolyte is known as solubility product. (K_sp).

3. Common ion effect:
The dissociation of weak electrolyte (Weak acid or weak base) is suppressed by the addition of a strong electrolyte having a common ion is called common ion effect.

4. Buffer solution:
Buffer solutions are solutions which retain their pH constant or unaltered after addition of less quantity of acid or base.

Question 5.
Before precipitation of IIIrd group radicals as hydroxides on adding NH₄OH, why it is necessary to add NH₄Cl first?
Answer:
Precipitation of hydroxide of group ill:
Radicals of group III i e.. Al³⁺, Fe³⁺, Cr³⁺ gets precipitated as hydroxides. Radicals cf succeeding groups such as Zn²⁺, Ni²⁺, Mg²⁺, etc. are also precipitated as hydroxide. (MPBoardSolutions.com) Solubility product of hydroxide of group III is lesser than that of other as given below:
Table: Solubility Product of Hydroxide at 18°C

Due to the difference in the solubility product of the hydroxides, concentration of OH^– ion is kept low such that only radicals of group III gets precipitated.
Hence, NH₄OH is added before adding NH₄Cl which remains completely ionized. Due to common (NH₄⁺) ion dissociation of weak electrolyte NH₄OH is suppressed.
NH₄Cl ⇄ NH₄⁺ + Cl^– (More ionised)
NH₄OH ⇄ NH₄⁺ + OH^– (Less ionised)
This decreases comcentration of OH^– ion and only hydroxides with low solubility product gets precipated.

Equilibrium Long Answer Type Questions – II

Question 1.
Derive a relation between equilibrium constant K_p and K_c, Or, Prove that K_p = K_cRT^∆n?
Answer:
In year 1867 Guldberg and Waage put forward a relationship between the rate of reaction and the molar concentration of reactants. The reUucrjhip is.0 as law of mass action. (MPBoardSolutions.com) It states that “At constant temperature, the rate of a chemical reaction is directly proportional to the product of the molar concentration of the reaction each raised to a power equal to its corresponding stoichiometric coefficient that appears in the balanced chemical equation.”
Example: For solids and liquids: Consider a hypothetical reversible reaction in the state of equilibrium.
A + B ⇄ X + Y
Applying law of mass action: Rate of forward reaction
R_f ∝ [A] [B] or R_f = K_f[A][B] ……………… (1)
Where, K_f is rate constant or velocity constant for the forward reaction. Similarly, rate of backward reaction,
R_b ∝ [X] [Y] or R_b = K_b [X][Y] ………………… (2)
Where, K_b rate constant or velocity constant for the backward reaction.
At equlibrium,
Rate of forward reaction = Rate of backward reaction.
K_f[A][B] = K_b[X][Y]

Its value remains constant at particular temperature. The equation (3) is called law of chemical equilibrium. For a general type of the reaction,
aA + bB ⇄ xX + yY

For gaseous reactants and products:
In the expression for K_c, the concentrations of the various species are generally expressed in terms of moles/litre. (MPBoardSolutions.com) However, in case of gaseous reactions the concentrations of gases may also expressed in terms of their partial pressures. Therefore, for a gaseous reaction:
aA + bB ⇄ xX + yY
The law of chemical equilibrium may be expressed as:

Relationship between K_pc:
Let us consider the following general reaction,
aA + bB ⇄ xX + yY
In which all the substances A, B, X and Y are present in gaseous state. For this reaction, K_p and K_c is written as follows:

Since, for an ideal gas,
PV = nRT
∴ P = \(\frac{n}{V}\) RT = CRT ………………… (3)
Where, the term C (equal to \(\frac{n}{V}\)) represents the molar concentration of the gas. On the basis of equation (3), we have
P_A = C_ART = [A] RT
P_B = C_BRT = [B] RT
P_X = C_X RT = [X] RT
P_Y = C_Y RT = [Y] RT
Substituting this value in equation (2), we get

Proved.

Question 2.
Derive Ostwald’s dilution law of ionization of weak electrolytes? Write its limitations?
Or, Deduce the relationship between degree of ionization and ionization constant?
Answer:
Ostwald’s dilution law: Weak electrolytes are partially ionised. The ions produced due to ionisation of weak electrolyte exist in dynamic equilibrium with the undissociated molecules.
The fraction of the total number of molecules of electrolyte dissolved, which ionises at equilibrium is called degree of ionisation or degree of dissociation. It is denoted by α.
Consider ‘C’ mol per litre be the initial concentration of weak electrolyte AB dissolved in water. Let α be its degree of ionisation. (MPBoardSolutions.com) Thus, the molar concentration of different species before ionisation and at equilibrium be as given below:

Under normal conditions, value of a is very small for weak electrolyte and it can be neglected in comparison to 1.
∴K = Cα²
or α² = \(\frac{K}{C}\)
∴α = \(\sqrt { \frac { K }{ C } } \)
If V is the volume of the solution in litres containing 1 mole of electolyte, then C = \(\frac{1}{V}\). Thus,
α = \(\sqrt { KV } \)
The above equation helps us to conclude that:
The degree of ionisation is inversely proportional to the square root of the molar concentration or directly propotional to the square root of the volume of the solution containing one mole of electrolyte. This is called Ostwald’s dilution law.

Limitations:
This law is not applicable for strong electrolyte and concentrated solutions because attractive force also acts between the solutions of such electrolytes.

Question 3.
Derive a relationship between pH and pOH value? Or, Prove that pH + pOH = 14.
Answer:
The water ionizes as:
H₂O + H₂O ⇄ H₃O⁺ + OH^–
K = \(\frac { [H_{ 3 }O^{ + }][OH^{ – }] }{ [H_{ 2 }O]^{ 2 } } \)
K [H₂O ]² = [H₃O⁺] [OH^–]
[∵K [H₂O ]² = K_w]
K_w = [H₃O⁺][OH^–] ……………. (1)
K_w is a constant, it is called product solubility.
At 298K, Temperature K_w = 1 × 10^-14.
On putting the value in equation (1)
10^-14 = [H₃O⁺][OH^–]
Taking log on both sides,
-14 log₁₀10 = log₁₀[H₃O⁺] + log₁₀[OH^–]
-14 = log₁₀[H₃O⁺] + log₁₀[OH^–], [∵log₁₀10 = 1]
0r 14 = [-log₁₀[H₃O⁺]] + [-log₁₀[OH^–]]
[∵log₁₀ [H₃O⁺] = pH]
[∵log₁₀ [OH^–] = pOH]
14 = pH + pOH

Question 4.
For the determination of pH value of buffer solution derive Henderson – Hazel equation?
Answer:
Henderson’s equation:
pH of a buffer solution can be calculated with the help of Henderson’s equation. For this consider a buffer of weak acid HA and its salt.
HA ⇄ H⁺ + A^–
K_a = \(\frac { [H^{ + }][A^{ – }] }{ [HA] } \)
K_a is dissociation constant of acid.
or [H⁺] = K_a \(\frac { [HA] }{ [A^{ – }] } \)
Salt is completely ionised while due to presence of excess A^– from the salt, the dissociation of weak acid will be depressed more due to common ion effect.
or [H⁺] = K_a \(\frac { [Acid] }{ [Salt] } \) [A^–] ≈ [Salt]
Taking log value,

This equation is called Henderson equation.
In the same way, for basic buffer solution:

pH of a buffer solution does not change woth dilution because on dilution the ration of conc. of acid or base does not change.

MP Board Class 11 Chemistry Important Questions

MP Board Class 12th Chemistry Important Questions Chapter 1 The Solid State

The Solid State Important Questions

The Solid State Objective Type Questions

Question 1.
Choose the correct answers:

Question 1.
Due to Frankel defect, density of ionic solids :
(a) Decreases
(b) Increases
(c) Does not change
(d) It changes.
Answer:
(c) Does not change

Question 2.
In CsCl each Cl is surrounded by how many Cs :
(a) 8
(b) 6
(c) 4
(d) 2.
Answer:
(a) 8

Question 3.
Frenkel defect is not shown by :
(a) AgBr
(b) AgCl
(c) KBr
(d) ZnS.
Answer:
(c) KBr

Question 4.
In NaCl crystal number of oppositely charged ions situated at equal distance are:
(a) 8
(b) 6
(c) 4
(d) 2
Answer:
(b) 6

Question 5.
Best conductor of electricity is :
(a) Diamond
(b) Graphite
(c) Silicon
(d) Carbon (non – crystalline).
Answer:
(b) Graphite

Question 6.
Which type of point defect is found in NaCI crystal of KCl crystal: (MP 2009 Set D)
(a) Frenkel defect
(b) Schottky defect
(c) Lattice defect
(d) Impurity defect.
Answer:
(b) Schottky defect

Question 7.
How many space lattices (Bravais lattice) can be obtained from various crystal systems :
(a) 7
(b) 14
(c) 32
(d) 230.
Answer:
(b) 14

Question 8.
Diamond is a :
(a) H – bond solid
(b) Ionic solid
(c) Covalent solid
(d) Glass
Answer:
(c) Covalent solid

Question 9.
The Co – ordination number of Ca²⁺ ions in fluoride structure is :
(a) 4
(b) 6
(c) 8
(d) 3.
Answer:
(c) 8

Question 10.
8 : 8 Co – ordination number is found in which compound :
(a) MgO
(b) A1203
(C) CsCl
(d) All of these
Answer:
(C) CsCl

Question 11.
Co – ordination number of body centred cubic cell is :
(a) 8
(b) 12
(c) 6
(d) 4
Answer:
(a) 8

Question 12.
Density of unit cell is :
(a) \(\frac { ZM }{ { a }^{ 3 }{ N }_{ 0 } } \)
(b) \(\frac { Z{ N }_{ 0 } }{ { a }^{ 3 }M } \)
(c) \(\frac { { N }_{ 0\quad }{ a }^{ 3 } }{ Z } \)
(d) \(\frac { Z }{ M{ N }_{ 0 } } \)
Answer:
(a) \(\frac { ZM }{ { a }^{ 3 }{ N }_{ 0 } } \)

Question 13.
The number of tetrahedral voids in unit cell of cubic close packing :
(a) 4
(b) 8
(c) 6
(d) 2
Answer:
(b) 8

Question 14.
Intra – ionic distance of CsCl will be :
(a) a
(b) \(\frac {a}{2}\)
(c) \(\frac { \sqrt { 3 } a }{ 2 } \)
(d) \(\frac { 2a }{ \sqrt { 3 } } \)
Answer:
(c) \(\frac { \sqrt { 3 } a }{ 2 } \)

Question 15.
Number of atoms in a body centred cubic unit cell is : (MP 2011)
(a) 1
(b) 2
(c) 3
(d) 4.
Answer:
(b) 2

Question 16
Which of the following is Bragg equation :
(a) nλ = 2ϕ sinθ
(b) nλ = 2d sinθ
(c) nλ = sinθ
(d) n\(\frac {θ}{2}\) = \(\frac {d}{2}\) sinθ.
Answer:
(b) nλ = 2d sinθ

Question 17.
Constituents of covalent crystal is :
(a) Atom
(b) Molecule
(c) Ion
(d) All of these.
Answer:
(a) Atom

Question 18.
Number of Na atom present in the unit cell of NaCI crystal is : (MP 2012)
(a) 1
(b) 2
(c) 3
(d) 4.
Answer:
(d) 4.

Question 19.
What type of magnetic substance are Fe, Co, Ni: (MP 2012,18)
(a) Paramagnetic
(b) Ferromagnetic
(c) Diamagnetic
(d) Antiferromagnetic.
Answer:
(b) Ferromagnetic

Question 20.
The correct example of Frenkel defect is : (MP 2012)
(a) NaCI
(b) CsCl
(c) KCl
(d) AgCl.
Answer:
(d) AgCl.

Question 21.
Dry ice (solid CO₂) is a/an : (MP 2012)
(a) Ionic crystal
(b) Covalent crystal
(c) Molecular crystal
(d) Metallic crystal.
Answer:
(c) Molecular crystal

Question 22.
Co – ordination number of Cs in CsCl: (MP2015)
(a) Like Cl i.e., 8
(b) Unlike Cl i.e., 6
(c) Unlike Cl i.e., 8
(d) Like Cl i.e., 6.
Answer:
(a) Like Cl i.e., 8

Question 23.
Structure of NaCI crystal: (MP 2015)
(a) Tetragonal
(b) Cubic
(c) Orthorhombic
(d) Monoclinic.
Answer:
(b) Cubic

Question 24.
Each Na⁺ion in NaCI crystal is surrounded by :
(a) Three Cl^– ions
(b) Eight Cl^– ions
(c) Four Cl^– ions
(d) Six Cl^– ions.
Answer:
(d) Six Cl^– ions.

Question 25.
For increasing of electro conductivity in a solid crystal, mixing of impurities is known as : (MP2016)
(a) Schottky defect
(b) Frenkel defect
(c) Doping
(d) Electronic defect.
Answer:
(c) Doping

Question 26.
Which type of lattice is found in KCl crystal:
(a) Face centred cubic
(b) Body centred cubic
(c) Simple cubic
(d) Simple tetragonal.
Answer:
(a) Face centred cubic

Question 27.
Number of atoms in a body centred cubic unit cell of a monoatomic substance is :
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(b) 2

Question 28.
Radius ratio limit for tetrahedral symmetry is :
(a) 0155
(b) 0.414
(c) 0.732
(d) 0.225
Answer:
(d) 0.225

Question 29.
The defect produced due to a cation and an anion vacancy in a crystal lattice is known as :
(a) Schottky defect
(b) Frenkel defect
(c) Crystal defect
(d) Ionic defect
Answer:
(a) Schottky defect

Question 30.
If co – ordination number of Cs⁺ is 8 in CsCl then co – ordination number of Cl^– ion is :
(a) 8
(b) 4
(c) 6
(d) 12
Answer:
(a) 8

Question 2.
Answer in one word / sentence :

1. Give two examples of metallic crystal.
2. Give two examples of covalent crystal.
3. Give two examples of ionic crystal.
4. What is the co – ordination number of F⁺ ion in CaF₁?
5. What is the value of co – ordination number of hexagonal close packing structure?
6. What is the type of structure of NaCl crystal?
7. Give an example of body centred cubic cell.
8. Give an example of a compound which has both Schottky and Frenkel type of defect.
9. What types of crystal is SiC? (MP 2011)
10. Write Bragg equation. (MP2017)
11. What is effect on the density of a substance or crystal due to Schottky defect?
12. Write the formula of radius ratio.
13. Give two examples of amorphous or non – crystalline solid.
14. F – centres give colour of crystal due to whose presence? (MP 2018)

Answer:

1. Copper, Nickel
2. Diamond, Graphite
3. NaCl, NaNO₃
4. 4
5. 12
6. Cubic
7. CsCl
8. AgBr
9. Covalent solid
10. nλ = 2d sinθ
11. Due to Schottky defect density of substance decreases
12. Radius ratio = \(\frac { radiusofcation\quad { r }^{ + } }{ radiusofanion\quad { r- } } \)
13. Glass, plastic
14. Due to presence of free electron.

Question 3.
Fill in the blanks :

1. The defect produced due to removal of a cation and an anion from a crystal lattice is called …………………. (MP 2018)
2. If in a crystal lattice a cation leaves its lattice site and occupies a space in the interstitial site then the defect is called ………………….
3. The cause of electric conduction of NaCl in its molten state are its ………………….
4. Due to …………………. defect the density of crystal decreases
5. Total …………………. types of crystal system are there.
6.  …………………. proposed the concept of atom for the first time.
7. The ratio of the cation and anion present in a crystal is known as ………………….
8. The process of adding small amount of impurities in an element or compound is called …………………. (MP 2018)
9. Total 14 types of unit cells are there which are known as ………………….
10. In NaCl crystal structure, co – ordination number of both Na⁺and Cl^– ion is ………………….
11.  …………………. defect is found in ZnS and AgCl crystal.
12. Due to Schottky defect, density of crystal ………………….
13. In metallic solids, conductivity is due to the presence of ………………….
14. Point defects are found in …………………. crystals.
15. Substances which are attracted in magnetic field are called ………………….
16. For a unit cell, if r = \(\frac { a }{ \sqrt { 8 } } \), then it will be …………………. type of unit cell.
17. Conductivity of semiconductor …………………. on increasing temperature.

Answer:

1. Schottky defect
2. Frenkel defect
3. Free ions
4. Schottky
5. Seven
6. Kannad
7. Radius ratio
8. Doping
9. Bravais lattice
10. Six
11. Frenkel
12. Decreases
13. Free electron
14. Ionic
15. Paramagnetic substance
16. Fcc
17. Increases.

Question 4.
Match the following:
I. (MP2014)

Answer:

1. (b)
2. (d)
3. (c)
4. (a)

II.

Answer:

1. (c)
2. (d)
3. (a)
4. (b)

III.

Answer:

1. (d)
2. (c)
3. (b)
4. (a)

IV. (MP2017)

Answer:

1. (c)
2. (d)
3. (a)
4. (b)

MP Board Class 12th Chemistry Important Questions

MP Board Class 12th Economics Important Questions Unit 10 Balance of Payments

Balance of Payments Important Questions

Balance of Payments Objective Type Questions

Question 1.
Choose the correct answers:

Question 1.
Structure of balance of payment includes which account:
(a) Current account
(b) Capital account
(c) Both (a) and (b)
(d) None of these.
Answer:
(c) Both (a) and (b)

Question 2.
Balance of trade means :
(a) Capital transactions
(b)Import and export of goods,
(c) Total credit and debit
(d) All of the above.
Answer:
(b)Import and export of goods,

Question 3.
Measures to improve adverse balance of payment includes :
(a) Currency devaluation
(b) Import substitution
(c) Exchange control
(d) All of the above.
Answer:
(d) All of the above.

Question 4.
Foreign Exchange Rate is determined by :
(a) Demand of foreign currency
(b) Supply of foreign currency
(c) Demand and supply in foreign exchange market
(d) None of these.
Answer:
(c) Demand and supply in foreign exchange market

Question 5.
Types of Foreign Exchange Market are :
(a) Spot market
(b) Forward market
(c) Both (a) and (b)
(d) None of these.
Answer:
(c) Both (a) and (b)

Question 2.
Fill in the blanks:

1. Bretton woods system is also known as ………………… border system.
2. There is ………………… relation between foreign exchange rate and the supply of foreign exchange.
3. By devaluation, the value of currency …………………
4.  ………………… items are included in the balance of trade.
5. Balance of payment always remains …………………
6. The value of currency of one country with that of the currency of another country is called …………………

Answer:

1. Adaptable
2. Direct
3. Reduces
4. Visible
5. Balanced
6. Exchange rate.

Question 3.
State true or false :

1. Balance of trade includes both visible and invisible items.
2. Balance of trade is a part of Balance of payments.
3. Devaluation is declared by the government.
4. Balance of payment is always balanced.
5. For export promotion, help of devaluation is taken.
6. The increasing population in developing countries has direct impact on economic growth.
7. Export promotion is one of the ways of correcting Balance of payments.

Answer:

1. False
2. True
3. True
4. True
5. True
6. False
7. False.

Question 4.
Match the following :

Answer:

1. (b)
2. (c)
3. (a)
4. (e)
5. (d)

Question 5.
Answer the following one word/ sentence:

1. New trade policy was declared in which year?
2. What will be the effect of devaluation of Indian currency on Indian imports?
3. In the long run, for what do the importers pay?
4. What does capital account imply?
5. What is the exchange of currency of one country in currency of another country called?

Answer:

1. 1991
2. Costly
3. Exports
4. International exchange and Indebtness
5. Ex – change Rate.

Balance of Payments Very Short Answer Type Questions

Question 1.
What is Balance of Payment?
Answer:
The balance of payment of a nation consists of the payments made, within a particular period of time between the residents of the country and the residents of foreign countries.

Question 2.
What do you mean by foreign exchange rate?
Answer:
Meaning:
The rate at which one currency buys or exchanges another currency is known as the rate of exchange. It simply expresses its external value or purchasing power. Foreign exchange rate between the currency units of two countries means the number of units of one national currency that are needed to buy one unit of other national currency.

Question 3.
Differentiate between Balance of Trade and Balance of Payment.
Answer:
Difference between Balance of Trade and Balance of Payment:
Balance of Trade:
The difference between exports and imports is called balance of trade.

Balance of Payment:
The difference between the total receipts of foreign exchange and total payment of foreign exchange is called balance of payment.

Question 4.
What do you mean by unfavourable balance of payment? Explain.
Answer:
Unfavourable balance of payment:
It is also called the deficit balance of payment. It refers to the situation when the total liability for payments of a nation exceeds the total receipts from foreign countries. Hence certain additional transactions are necessary to balance it such as export of gold, withdrawal of deposits in foreign banks etc.

Question 5.
What do you mean by capital account?
Answer:
Capital account is that account of balance of payment which records all such transactions between the residents of a country and rest of the world which cause a change in asset or liability of the country.

Question 6.
What do you mean by current account of balance of payment?
Answer:
Current account is that account of balance of payment which records imports and exports of goods and services and unilateral transfers. It includes visible, invisible and unilateral transfers.

Question 7.
What do you mean by managed floating system?
Answer:
Managed floating system is a mixture of flexible exchange rate system and fixed rate system. (The float part + managed part). Under this system the central bank tend to intervene to buy and sell foreign currencies in an attempt to reduce fluctuation in exchange rate.

Question 8.
What do you mean by protection?
Answer:
When by ending the freedom of foreign trade the ban is put on import and export of goods it is called protection.

Question 9.
Write one advantage of open economy?
Answer:
Investors get the choice of selection among domestic products and foreign goods.

Question 10.
What do you mean by dumping?
Answer:
When the goods are excess than demand then the seller sells this goods in foreign countries on lower rate it is called dumping.

Question 11.
Write points in favour of fixed exchange rate.
Answer:

1. To encourage international trade.
2. Formation of capital.
3. Encouragement to foreign capital
4. Encouragement to export countries.

Question 12.
What do you mean by foreign trade multiplier?
Answer:
Foreign exchange rate multiplier tells us how many times increase takes place in national income by increasing in export.

Question 13.
What does a balance of payment record?
Answer:
The balance of payment records the transaction in goods and services and assets between residents of a country with the rest of the world.

Question 14.
What is dirty floating?
Answer:
When managed floating in the absence of rules and guidelines are implemented, it is called dirty managed floating system.

Question 15.
What do you mean by import and export?
Answer:
Import:
When goods and services are brought from the foreign countries to the domestic countries it is called import.

Export:
Goods and services are send to foreign countries from domestic countries.

Question 16.
What does foreign exchange market include?
Answer:
Foreign exchange market includes banks specialised foreign exchange dealers, brokers, government agencies through which the currency of one country can be exchanged for that of other country.

Question 17.
What do you mean by flexible exchange rate?
Answer:
Flexible rate of exchange:
It is freely determined by the prices of supply and demand in the internal market.

Question 18.
What do you understand by managed floating rate system?
Answer:
It is a hybrid of a fixed exchange rate and flexible exchange rate system. In this system, central bank intervenes in the foreign exchange market to restrict the fluctuations in the exchange rate within certain limits. The aim is to keep exchange rate close to desired target values.

Question 19.
Give arguments in favour of fixed exchange rate.
Answer:
Following points can be studied in favour of fixed exchange rate:

1. Encouragement to international trade.
2. Encouragement to foreign capital.
3. Capital formation.

Question 20.
Write points against fixed exchange rate.
Answer:
Following are the points against fixed exchange rate :

1. Controlled economy.
2. Encouragement to corruption.
3. Sudden change in exchange rate.
4. Unfavourable effect on economic development.

Question 21.
Explain two merits and two demerits of fixed foreign exchange rate.
Answer:
(a) Two merits of fixed foreign exchange rate :

1. Fixed foreign exchange rate ensures stability in exchange rate. The exporters and importers do not have to operate under uncertainty about the exchange rate. Thus, it promotes foreign trade.
2. It also promotes capital movements.

(b) Two demerits of fixed foreign exchange rate :

1. Under this system, countries with deficit in balance of payment run down the stock of gold and foreign currencies. This can create serious problem for them.
2. There may be undervaluation of currency.

Question 22.
Write down the advantages of fixed exchange rate system.
Answer:
Advantages of fixed exchange rate system :

1. This system ensures stability in the international money market/ exchange market.
2. It encourages international trade.
3. It promotes bilateral trade agreements.
4. It avoids speculation.
5. It keeps the government under pressure to combat inflation.

Balance of Payments Short Answer Type Questions

Question 1.
What do you mean by fixed exchange rate? Write three points against it.
Answer:
A fixed exchange rate is a regime applied by a country whereby the government or central bank ties the official exchange rate to another country’s currency or the price of gold. The purpose of a fixed exchange rate system is to keep a currency’s value within a narrow band.

Following are the different points against the fixed exchange rate:
1. Controlled economic system:
For fixed rate of exchange it is compulsory to have strict control over economic system. If it is not possible then we will have to make changes in exchange rate.

2. Unfavourable effect on economic progress :
The main aim of fixed rate of exchange is to maintain stability in exchange rate. In this situation sometimes national income, employment policy, price level etc. are considered as secondary.

3. Corruption:
To maintain fixed exchange rate many restrictions are imposed in the country. Due to strict restrictions there is always possibility of corruption in the society.

4. Sudden change in the exchange rate:
Some times it becomes evitable to make changes in exchange rate. To keep the exchange rate stable some times currency of the nation becomes weak. In such stuation sometimes the there is devaluation. It has adverse effect on foreign trade and balance of payment.

Question 2.
What is meant by flexible exchange rate? Give arguments in favour and against flexible exchange rate.
Answer:
A system in which rate of exchange is determined by the sources of demand and supply of different currencies in foreign exchange market.

Following points which can be studied in favour of flexible exchange rate :

1. Independent economic policy : If the exchange rates are elastic any country can make their domestic economic policies internal policies) independently.

2. Implementation of monetary policy independently : If the rate of exchange is flexible monetary policy in the nation can be independently and effectively by changing the monetary policy.

Following points which can be studied against the flexible exchange rate :

1. Adverse economic effect:
If the flexible exchange rate is there then the feeling of insecurity comes in the minds of traders. It has an adverse effect on the foreign trade of the country. The tendency of gambling increases. If the exchange rate is reduced the inflation increases. The level of employment opportunities also go down.

2. Misuse of the resouroes:
If exchange rate goes on changing very often then the resources have to distributed again and again sometimes the resources are used in export sometimes for domestic industries. Due to these changes there is always wastage of resources.

Question 3.
What do you mean by balance of payment? What are the causes of adverse balance payment in India?
Or
Explain four causes of adverse balance of payment.
Answer:
Meaning of balance of payment:
The balance of payment of a nation consists of the payments made, within a particular period of time between the residents of the country and the residents of foreign countries.

Following are the causes of adverse balance of payment in India:
1. Increase in imports of petroleum products:
Oil producing countries are increasing the price of petroleum products every year. Along with it the consumption of petroleum products is also increasing day by day. Due to this import is done on lkrge scale.

2. Increase in import of machines:
Due to economic planning there is rapid growth in industrialization and progress in agricultural development. For this the need of machines was felt. Due to this reason more import has to be done.

3. Less increase in export:
The export did not increase according to expectations which is one of the causes of unfavourable balance of payment.

4. International loans and investment:
India has taken loan for developmental purpose. To repay the principal amount and interest, foreign exchange has to be paid. It gave rise to the situation of adverse balance of payment.

Question 4.
Suggest measures to improve the condition of adverse balance of payment
Answer:
Measures or method to correct adverse balance of payment : Following steps should be taken to improve adverse balance of payment in India :

1. Encouragement to export:
The government should encourage the export.

• The trade policy should be export oriented
• For this export tax should be reduced or some concession should be given for export of some goods
• Economic assistance should be provided to the industries of the country
• Advertisement should be done in foreign countries for the products.

2. Reduction in import:
India should reduce imports. For this import duty should be raised so, that imported goods will become expensive and people will be discouraged to purchase them. Domestic products should be discouraged reduce the imports. It will give rise to favourable balance of payment.

3. Foreign debt:
To remove adverse balance payment government can take foreign loan. But taking loan is a temporary solution of it.

4. Exchange control:
For keeping the balance payment exchange control is one method. By controlling exchange we can reduce import and increase export.

Question 5.
Give arguments in favour and against fixed exchange rate.
Or
Give arguments in favour of fixed exchange rate.
Answer:
Follo’wing are the points which can be studied in favour of fixed exchange rate :

1. Encouragement to international trade:
Under fixed exchange rate both importer and exporter know about the amount he has to pay and how much he will be getting. Thus in fixed exchange rate international trade develops in a balance way. Here there is less risk.

2. Encouragement to foreign capital:
If the exchange rate is stable foreign exchange can easily flow into the country because investor is not scared of getting less amount than what is fixed. There is no fear of bearing of loss if the rate of exchange is reduced.

3. Capital formation:
If the foreign exchange rate is fixed there is a favourable effect on internal condition of the country. There is no fear of inflation. In industry demand of capital is increased, savings is also increased. Thus rate of capital formation increases. It gives rise to the development of the country.

4. Exchange system:
If the exchange rate is fixed it does not give encouragement to the tendency of gambling. Thus government can control the exchange system in proper way.

5. Essential for export countries:
Some of the country depend on the income coming from export. Half the national income of such countries comes from exports. For countries like England, Denmark, Japan etc. fixed rate of exchange is very essential otherwise there will be adverse effect on its development.

Following points are there against the fixed rate of exchange :

1. Controlled economic system:
For fixed rate of exchange it is compulsory to have strict controlled over economic system. If it is not possible then we will have to make changes in exchange rate.

2. Unfavourable effect on economic progress:
The main aim of fixed rate of exchange is to maintain stability in exchange rate. In this situation sometimes national income, employment policy, price level etc. are considered as secondary.

3. Corruption:
To maintain fixed exchange rate many restriction are imposed in the country. Due to strict restriction there is always possibility of corruption in the society.

Question 6.
Differentiate between Balance of Trade and Balance of Payment.
Answer:
Differences between Balance of Trade and Balance of Payment:

Balance of Trade:

• The difference between exports and imports is called balance of trade.
• It refers to detailed description of imports and exports only.
• It includes visible items only.
• It may be favourable and unfavourable.
• If balance of trade is not favourable it is not a cause of great concern.
• Balance of trade is a part of balance payment.

Balance of Payment:

• The difference between the total receipts of foreign exchange and total payment of foreign exchange is called balance of payment.
• It comprises not only exports and imports but also services, capital, gold etc.
• It includes visible as well as invisible items both.
• It is always balanced.
• If the balance of payment is not favourable it is a cause of great concern for the nation.
• The concept of balance of payment is broader.

Question 7.
Differentiate between devaluation and depreciation.
Answer:
Differences between devaluation and depreciation:
Devaluation means lowering the value of one’s currency in terms of foreign currency. In this case, the domestic value of currency remains constant but its value in terms of foreign currencies fall. On the other hand, the fall in the price of foreign exchange under flexible exchange rate is known . as depreciation. For instance, if the equilibrium rupee – dollar exchange rate was Rs. 45 and now it has become Rs.50 due to rise in demand for dollars, then the rupee has depreciated against dollar.

Question 8.
What is the marginal propensity to import when M = 60 + 0.06Y? What is the relationship between the marginal propensity to import and the aggregate demand function?
Answer:
M = 60 + 0.6Y (Given)
M = \(\overline { m } \) + mY
Hence, m = 0.6
Where, m = Marginal propensity to import

Relationship:
There is positive relationship between marginal propensity to import and aggregate demand function. Marginal propensity of income spent. Thus,
m = \(\frac {∆m}{∆n}\)

Question 9.
Explain, why:
G -T = (S^g -1) – (X – M)?
Answer:
G -T = (Sf -1) – (X – M)
Here, G = Government expenditure
T = Taxes
S^g = Saving of government
I – Investment
S^g-I = Net Saving
X = Exporters
M = Importers
X – M = Balance of trade.
The given equation states that net government expenditure equals net government savings and balance of trade. It implies that net government expenditure is financed by government savings and trade deficit. Hence, the given equation is correct.

Question 10.
Should a current account deficit be a cause for alarm? Explain.
Answer:
When a country runs a current account deficit, then he must see whether there has been a decrease in saving, increase in investment or an increase in the budget deficit. There is reason to worry about a country’s long prospects of the trade deficit reflects smaller savings or a larger budget deficit. The deficit could reflect higher private or government consumption. In such cases, the country’s capital stock will not rise rapidly enough to yield enough growth it needs to repay its debt. There is less cause to worry, if the trade deficit reflects a rise in investment, which would build the capital stock more quickly and increase future output.

Question 11.
Distinguish between Balance of Trade and Balance on Current Account.
Answer:
Differences between Balance of Trade and Balance on Current Account:

Balance of Trade Account:

• Balance of trade account records the difference between value of imports and exports of material goods (visible items). lateral transfer (visible and invisible)
• Balance of trade is a part of balance on current account. So, it is a narrow concept.

Balance on Current Account:

• Balance on current account records the difference between receipts and payments of foreign exchange on account of goods, services and uni – items).
• Balance on current account is a wide concept.

Question 12.
If inflation is higher in country A than in country B and the exchange rate between the two countries is fixed, what is likely to happen to the trade balance between two countries ?
Answer:
Effect of inflation on the trade balance:
As the inflation is higher in country A than country B, so the prices of country A will be higher as compared to those of country B. In this case exports of A country will fail. The aggregate demand will fall and output and income will fall. Comparatively less price in country B will make its products less expensive and hence again increases w.e.f. net export and domestic output and income. The trade balance of country A will become deficit.

Balance of Payments Long Answer Type Questions

Question 1.
Write the components of Balance of payment.
Answer:
The Balance of payment of a nation consist of the payments made, within a particular period of time between the residents of that country and the residents of foreign countries. (MPBoardSolutions.com) In other words, it is an account of transactions involving receipts from foreigners on one side and payments to foreigners on the other side. The farmer relates to the international income of a country, they are called “credits” and since the later relates to the international out go, they are call “debits”.

Balance of payment includes all other payments apart from export and import. For example fee of banks, interest, profit, transfer of capital etc. are also included in balance of payment.

Question 2.
Write the main components of capital accounts.
Answer:
The main components of capital accounts are :

1. Borrowings and lending to and from abroad: It includes :
All transactions relating to borrowings from abroad by private sectors, government, etc.
All transactions of lending to abroad by private sectors and government.

2. Investment to and from abroad:
Investments by rest of the world in shares of
Indian companies, real estate in India etc.
Investments by Indian residents in shares of foreign companies, real estate abroad, etc.

3. Change in foreign exchange reserves:
The foreign exchange reserves are the financial assets of the government held in the central bank.

Question 3.
Explain the factors affecting fluctuations in foreign exchange.
Answer:
The factors affecting fluctuations in foreign exchange :

1. Banking related effects:
Banks through their functions affect the exchange rate. If the commercial bank float bank draft and other credit letters in large quantity then the demand for foreign exchange increases and the exchange rate of the country currency decreases. On the other hand, when foreign exchange bank floats credit letters against the country then the demand for home currency increases and the exchange rate becomes favourable for the country.

2. Change in prices:
In comparative view the change in prices results in the change of exchange rate of the country.

3. Impact of imports and exports:
Changes in the import and export quantity of country has a direct impact on the countries exchange rate if export increases in comparison to import the demand for foreign exchange. (MPBoardSolutions.com) If exports increase in comparison to imports the demand for foreign exchange increases and the countries exchange rate becomes favourable. But on the other hand if imports increase then the demand for country currency increases in the foreign country and this becomes unfavourable for the country.

4. Impact of speculation:
The changing trend in speculation trends also have an impact on exchange rate. In short period the.high rate of exchange leads to speculation tendencies. The uncertainty of exchange rate in international money market also encourages speculative motive.

5. Flow of capital:
The flow of capital from a country also affects the exchange rate. Flow of capital from one country to another to earn high profits is possible in short period or flow of capital to foreign countries for investment in the long period in the foreign country is also possible.

Question 4.
Explain visible and invisible export and import.
Answer:
Visible Import and Exports:
Such goods are included in visible imports and exports whose account is maintained in the register of ports. By seeing them we can find out the values of import and export done throughout the year. (MPBoardSolutions.com) In it only the export and imports of goods are kept.

Invisible Import and Exports:
In invisible export and import we include services which exchange are included. They are banking services, insurance, shipping services, education in foreign, medical facilities, tourism, interest, profit, military assistance, foreign donation, penalty etc. whose account is not maintained on ports are included in it.

Question 5.
Suppose C =100 + 0.75Y, 0T = 500, G = 750, taxes are 20% of income. X = 150, M = 100 + 0.2Y. Calculate equilibrium income, the budget deficit or surplus and the trade deficit or surplus.
Answer:
C = 100 + 0.75 YD
Here, C = 100, C = 0.75, I = 500, G = 750, X = 150, M = 100 + 0.2Y
Tax income (r) = 20%
Income (Y) = C + C (1 – t) Y +1 + G + (X – M)
or Y = 100 + 0.75 (1 – 0.2)Y + 500 + 750 + (150 – 100 – 0.2Y)
or Y = 100 + 0.75(0.8) Y + 500 + 750 + 150 – 100 – 0.2Y
or Y= 100 + 0.6Y+ 1300 – 0.2Y
or = 1400 + 0.4Y
or Y – 0.4 Y = 1400
or 0.6Y = 1400
or Y = \(\frac {1400}{0.6}\) = 2333
Deficit budget = Govt. expenditure Tax – (G) – Tax
= 750 – 2333 of 20 %
= 750 – 467 = 283
M = 100 + 0.2Y
= 100 + 0.2 (2333)
= 100 + 467 = 567
So, Trade deficit = M – X = 567 – 150 = 417.

MP Board Class 12th Economics Important Questions

MP Board Class 12th Economics Important Questions Unit 9 Government Budget and Economy

Government Budget and Economy Important Questions

Government Budget and Economy Objective Type Questions

Question 1.
Choose the correct answers:

Question 1.
The duration of Government budget is :
(a) 5 years
(b) 2 years
(c) 1 year
(d) 10 years.
Answer:
(c) 1 year

Question 2.
Budget is presented in the Parliament by :
(a) Prime Minister
(b) Home Minister
(c) Finance Minister
(d) Defence Minister.
Answer:
(c) Finance Minister

Question 3.
Budget speech in Lok Sabha is given by :
(a) President
(b) Prime Minister
(c) Finance Minister
(d) Home Minister.
Answer:
(c) Finance Minister

Question 4.
Professional tax is imposed by :
(a) Central Government
(b) State Government
(c) Municipal Corporation
(d) Gram Panchayat.
Answers:
(b) State Government

Question 5.
From the following which is included in the direct tax :
(a) Income Tax
(b) Gift Tax
(c) Both (a) and (b)
(d) Excise Tax.
Answer:
(c) Both (a) and (b)

Question 6.
Who issues 1 rupee note in India :
(a) Reserve Bank of India
(b) Finace Ministry of India
(c) State Bank of India
(d) None of these.
Answer:
(b) Finace Ministry of India

Question 2.
Fill in the blanks:

1. …………………… is a document containing income and expenditure of the government.
2. Income tax is …………………… tax.
3. …………………… tax is levied on the value of the goods.
4. Service tax is levied by the ……………………
5. budget is considered good for the country.
6. Finance bill contains …………………… proposals.
7. Government budget is presented on the last day of ……………………

Answer:

1. Budget
2. Direct
3. Advalorem
4. Central
5. Deficit
6. Tax
7. February.

Question 3.
State true or false :

1. Deficit budget is not considered as a good budget.
2. Electricity tax is levied by the State Government.
3. Budget speech is given by the Finance Minister.
4. Central excise duty is direct tax.
5. Interest payment is a planned item.
6. During deflation surplus budget is made.
7. Rail budget is generally not included in the annual budget.

Answer:

1. False
2. True
3. True
4. False
5. False
6. True
7. True.

Question 4.
Match the following

Answer:

1. (b)
2. (d)
3. (a)
4. (e)
5. (c)

Question 5.
Answer the following in one word/sentence :

1. Write meaning of surplus budget.
2. Expenditure on education is considered as?
3. Who passes the budget presented by the Finance Minister every year?
4. Which tax was levied by the government on July 2017?
5. For how many years government makes budget?
6. What is the full form of G.S.T.?
7. Land Revenue is levied by whom?
8. What is the name gives to budget?

Answer:

1. More income and less expenditure
2. Developmental
3. Parliament
4. G. S. T
5. 1 year
6. Goods and Service Tax
7. By State Government
8. Master Finacial Scheme of Government.

Government Budget and Economy Very Short Answer Type Questions

Question 1.
What do you mean by government budget? How many types are there?
Answer:
A budget is the statement of financial plan of the government for a financial year (1st April to 31st March). It indicates the revenue expenditure estimates for the next financial year of the government.

Budget is of two types:

1. Capital budget
2. Revenue budget.

Question 2.
What do you mean by primary deficit?
Answer:
Primary deficit is the difference between fiscal deficit and interest payments. It indicates how much government borrowing is going to meet expenses other than interest payments. It is often used as the basic measure of fiscal responsibility.
Primary Deficit = Fiscal Deficit – Interest payments

Question 3.
What is tax?
Answer:
A tax is a compulsory contribution which is given by the people to the government in order to meet the expenditure on the welfare of the citizens.

Question 4.
What is deficit budget?
Answer:
When the expenditure of the government is more than the income of the government, it is called deficit budget.

Question 5.
What do you mean by supplementary budget?
Answer:
Supplementary budget is prepared for the temporary period. It is prepared during the period of emergency like flood, war, earthquake etc.

Question 6.
What do you mean by zero primary deficit?
Answer:
When government has to take loan only to fulfill the liability of interest it is called zero primary deficit.

Question 7.
What do you mean by vote on account?
Answer:
Special arrangement is made under which special power is vested with lok sabha to sanction some amount as advance till the financial budget is passed for the next year.

Question 8.
What is tax evasion?
Answer:
When people do not pay tax by hiding income it is called tax evasion.

Question 9.
What do you mean by surplus budget?
Answer:
When the income of the government is more than expenditure of the government in budget, it is called surplus budget.

Question 10.
What is a balanced budget?
Answer:
Budget in which income and expenditure of the government is equal is called balanced budget.

Question 11.
Write the tax multiplier.
Answer:
Tax multiplier = \(\frac {-c}{1 – c}\)

Question 12.
What do you mean by debt trap?
Answer:
Generally developing countries take loans from foreign countries to fulfill their projects and plans. Developing countries have to pay debt along with the interest on it. To pay this amount again government has to take loan. Thus, principal amount goes on increasing. These countries take loan from one country and pay loan of other country. Thus these countries go in the clutches of debt. This is called debt trap.

Question 13.
Write the main revenue sources.
Answer:
Public revenue:
By public revenue we mean all those income of the government which are essential for government expenditure. Public revenue can be divided into two parts :

1. Revenue receipts
2. Capital receipts.

1. Revenue receipts (Items of income) are of two types :

(A) Tax revenue : It includes all direct and indirect taxes which are imposed by the central government. For example, Income Tax, Corporation Tax, Production tax.

(B) Non – tax revenue :

• Interest receipts
• Dividends and Profits
• Foreign grants
• Fiscal services, Economic services, Subsidiary assistance.

Question 14.
Give the relationship between the Revenue deficit and the Fiscal deficit.
Answer:
Revenue deficit refers to the excess of Government’s revenue expenditure over revenue receipts whereas fiscal deficit is the difference between the government’s total expenditure and its total receipts excluding borrowings.

Question 15.
Explain why public goods must be provided by the government.
Answer:
Public goods must be provided by the government as they cannot be provided through market mechanism i.e., by transactions between individual consumer and producers.

Question 16.
Explain the relation between government deficit and government debt.
Answer:
Relation between government deficit and government debt: The government deficit and government debt are closely related. The government deficit in a flow concept, but it adds to the stocked debt. If the government continues to borrow year after year there is an accumulation of debt. It implies that government has to pay more and more by way of interest. These interest payment contribute to the debt. Thus, deficit is the cause and effect of debt.

Question 17.
Explain the concept of Deficit budget.
Answer:
Deficit budget: It is the budget in which government receipts are more than government expenditure.
Formula = Expected public income < Expected public expenditure.

Government Budget and Economy Short Answer Type Questions

Question 1.
What is a government budget? Write its objectives. (Delhi, Foreign 2013)
Answer:
“A budget is the statement of the financial plan of the government for a financial year” (1st April to 31st March). It indicates the revenue expenditure estimates for the next financial year of the government. The main objectives of budget are as follows :

1. Reallocation of financial resources.
2. Removal of inequality of income and wealth.
3. Stabilization of price level.
4. Management of public enterprises.
5. Expansion of employment opportunities.

Question 2.
How inequalities in income can be removed through budget?
Or
What is the role of budget in removing income inequalities? (Delhi, All India 2011, Foreign 2012)
Answer:
Fiscal policy implies the income and expenditure policy or the budgetary policy of the government. It is a branch of public finance which deals with the types of financial statements made by any government about its probable revenue and expenditure during a given year.

Through their fiscal policies government can play a significant role in reducing inequality of income and wealth as well as inequality of opportunity. Both tax and spending policies can alter the distribution of income over both short term and medium term. Government need to reform the policies by imposing more taxes oh riches sections and to reduce the burden of tax on poor with the motive of economic welfare of the poor people.

Question 3.
Explain in brief how economic stability can be obtained by government budget? (All India 2011)
Answer:
Government budget is used to prevent business fluctuations of inflation or deflation to achieve the objective of economic stability. The government aims to control the different phases of business fluctuations through the budgetary policy. Policies of surplus budget during inflation and deficit budget during deflation helps to maintain stability of prices in the economy.

Question 4.
What is the role of government in Reallocation of Resources? Explain. (Delhi 2012)
Answer:
Through the budgetary policy, Government aims to reallocate resources in’ accordance with the economic and social priorities of the government. Government can influence allocations of resources through:

1. Tax concessions or subsidies:
To encourage investment, government can give tax concessions subsidies etc. to the producers, example Government discourages the production of harmful consumption goods through heavy taxes and encourages the use of khadi products ‘by providing subsidies.

There is disequilibrium in the balance of payments when imports are more and exports are less. With demonitization of Indian rupee imports have become costlier, efforts can be made to make balance of payments favourable. But this cannot be done again and again because by this demand of our currency will decrease.

Question 5.
Explain four types of public expenditure.
Answer:
Following are the types of public expenditure :

1. Developmental expenditure:
Under it we include those expenditure which are done for the economic development and social welfare of people. It includes education, medicine, industry agriculture, transportation roads, canals, water welfare, electricity etc.

2. Non – development expenditure:
This expenditure includes that expenditure which is done on administration, on security and legal procedure of the government. It includes salaries of police department, military department, interest on loans, pension etc.

3. Plan expenditure:
It includes expenditure to be incurred during the year on programmes under the five year plan by planning commission. In this expenditure investors and consumers both are included. For example, economic activities like agriculture, industry transportation, communication etc. It also includes social welfare activities like education, family welfare, information and communication, drinking water, cleanliness, health etc.

4. Non – plan expenditure:
It includes all those expenditure other than plan expenditure. It includes debt given to State Government and others, expenditure on maintenance of property, expenditure on purchase of shares.

Question 6.
Differentiate between Direct Tax and Indirect Tax
Answer:

Question 7.
Differentiate between Revenue Expenditure and Capital Expenditure.
Answer:
Differences between Revenue Expenditure and Capital Expenditure :

Revenue Expenditure:

• Revenue expenditure is a current expenditure incured on civil administrations, defence forces, public health and education.
• It is of recurring type of expenditure. It is incurred regularly.
• It is called non – developmental expenditure.

Capital Expenditure:

• It refers to expenditure which leads to creation of assets or reduces liabilities.
• It is a non – recurring type of expenditure.
• It is called developmental expenditure.

Question 8.
Differentiate between Developmental and Non – Developmental Expenditure.
Answer:
Differences between Developmental and Non – Developmental Expenditure:

Developmental Expenditure:

• It is incurred on economic and social development of the country.
• Expenditure on agriculture, industries, transport, etc. are included in it.

Non – Developmental Expenditure:

• Its nature is non – developmental type.
• Expenditure on administrative services like police defence, grants to government, etc. are included in it.

Question 9.
What do you mean by budget? Write its characteristics.
Answer:
Origin of the word in India:
The word ‘budget’ has been derived from the French word ‘Bougette’, which means small bag. It symbolizes a bag containing the financial proposals. In England, the chanceller used to bring economic proposals and statements in a bag; In 1773, finance minister of Britain, Robert Walpole opened his leather bag for the budget proposal to take place in Parliament. From that it becomes popular in India.

Characteristics of budget : Following are the characteristics of budget:

1. Annual plan of income and expenditure : It is a description of annual income and expenditure of the government for the next financial year. It is a detailed description.
2. Fixed period : Budget is prepared before a fixed period. It is presented before the Parliament by finance minister on the last day of the month of February. It is related to the definite fixed period.
3. Financial discussion: In budget only financial discussion takes place.Other matters are not discussed here.
4. In advance : Budget is prepared in advance for the period during which it is to operate. It is an annual financial action plan for the next financial year.
5. Balance budget : Balanced budget is the symbol of economic stability of the country.

Question 10.
Write the objectives of budget.
Answer:
The objectives of budget are as follows :
1. Reallocation of financial resources:
The government reallocates the financial resources to achieve the desired goals. It is the primary responsibility of the government to build a sound socio – economic infrastructure regarding health housing, education and raising the standard of living of people. Government imposed more taxes on those items which are harmful for people on the other hand it may reduce the taxes which are useful from social point of view.

2. Removal of inequality of income and wealth:
Every nation tries to bring equality between the various sections of the people and to bridge the gap between poor and rich. Through subsidies, taxes government can remove their inequalities. The main objective of Budget is to fill the gap of rich and poor.

3. Stabilisation of price level:
It is the responsibility of the government to stabilise the price level in the country. Unnecessary fluctuation in the prices of goods and services adversely affect the economy. Through the budget the government can effectively control the price level and bring about stability in it.

4. Management of public enterprises:
The government looks after certain departments such as railways, post and telegraph, electricity, defence etc. The budget of the government makes special provisions for such public enterprises in order to safeguard the interest of public.

5. Expansion of employment opportunities:
Government throughout budget create the employment opportunities to people. Various employments oriented and productive programs can be implemented for this purpose.

Question 11.
Differentiate between Progressive Tax and Regressive Tax.
Answer:
Differences between Progressive Tax and Regressive Tax :

Progressive Tax:

• In progressive tax the rate of the tax increses as the taxable income increases.
• The burden of it is more on rich people.
• They are justified because they reduce inequalities of income.

Regressive Tax:

• In regressive tax the rate of the tax decreases as the taxable incomes increases.
• The burden of it is on poor people.
• These are not justified because they increase inequalities.

Question 12.
Write difference betw een Revenue Receipts and Capital Receipts. (Foreign 2013)
Answer:
Differences between Revenue Receipts and Capital Receipts :

Question 13.
Write a note on Surplus budget, Balance budget and Deficit budget.
Answer:
A budget is the statement of the financial plan of the government for a financial year. It indicates the revenue expenditure estimates for the next financial year. The different types of budget are :

1. Surplus Budget – When in budget the income of the government is more than expenditure of the government, it is called Surplus Budget.
2. Balance Budget – Balance budget is said to be balance when government revenue and expenditure are balanced.
3. Deficit Budget – If the expenditure of the government is more than the income of the government, it is called the Deficit Budget.

Question 14.
Does public debt impose a burden? Explain.
Answer:
Public debt does not impose a burden all the times. Only in the following situation, it imposes a burden. When government sectors to public debt, the government transfers the burden to reduce consumption on future generation, because the government may decide to pay off deut in future by raising taxes. Taxes reduce the savings and capital formation and growth. Thus, the debt acts as a burden on future generation.

Question 15.
(a) The fiscal deficit given the borrowing requirement of the government. Explain.
Answer:
Fiscal deficit gives the borrowing requirement of the government’s total expenditure and its total receipts excluding borrowing. The fiscal deficit has to be financed through borrowing. Thus, it indicates the total borrowing requirements of the government from all sources.

(b) Are fiscal deficits inflationary? (NCERT)
Answer:
It is not correct to that all deficits are necessarily inflationary. If the fiscal deficit results in higher demand and greater output, the fiscal deficit will not be inflationary. However, if the firms are unable to produce the higher quantities that are being demanded to due fiscal deficits, prices will rise resulting the inflationary.

Question 16.
We suppose that: C= 70 + 0.70YD, I = 90, G = 100, T = 0.10 Y
(a) Find the equilibrium income, (b) What are tax revenues at equilibrium income? Does the government have a balanced budget ?
Solution:
(a) Y = \(\frac {1}{1 – 0.70}\)(70 + 90 + 100)
Y = \(\frac {1}{0.30}\)(260)
Y = \(\frac {260}{0.30}\) = 866.66

(b) Tax revenue on balance budget (T) = 0.10 Y T = 0.10 (866.66) T = 86.66.

Question 17.
Suppose that for a particular economy investment is equal to 200, government purchases are 150, net taxes i.e., lump sum taxes minus transfer in 100 and consumption is given by C = 100 + 0.75. (a) What is the level of equilibrium multiplier? (b) Calculate the value of government expenditure multiplier and the tax multiplier, (c) If government expenditure increases by 200, And the change in equilibrium income.
Answer:
(a) The government directly affects the level of equilibrium income in two specific ways : 1. Purchase of goods and services and 2. Taxes and transfers. Taxes lower the consumption expenditure and disposable income. Hence, we use the following formula for calculating the level of equilibrium income:
Formula: Y = \(\frac {1}{1-c}\)(C – CT + CTR+ 1 + G)

(b) Govt expenditure multiplier:
\(\frac { ∆Y}{∆G}\) = \(\frac {1}{1-c}\)
\(\frac { ∆Y}{∆G}\) = \(\frac {1}{ 1-0.75}\) \(\frac {1}{0.25}\)
Tax multiplier \(\frac { ∆Y}{∆G}\) = \(\frac {-C}{1-c}\)
\(\frac { ∆Y}{∆G}\) = \(\frac {-0.75}{ 1-0.75}\) = \(\frac {-0.75}{ 0.25}\) = – 3

(c) If income of Govt, increases by 200 :

Question 18.
In the equation given in question 9, calculate the effect on output of a 10 increase in transfers and 10 increase in lumpsum taxes. Compare the effects of two.
Solution:
Transfer multiplier, = \(\frac {C}{1-C}\)
= \(\frac {0.80}{1-0.80}\)
= \(\frac {0.80}{0.20}\)
= 4
Increase in transfer = 10%
Hence, increase in output = 10%
Tax multiplier = 4
Decrease in output = 10 x 4 = 40%
or
Y = \(\frac {1}{0.20}\)(20 – 8 + 88 + 30 + 50)
Y = 5 x 188 = 940
Increase lump sum, its effect,
or Y = \(\frac {1}{1-0.80}\)(20 – 8 + 80 + 30 + 50)
Y = 5 x 172 = 860.
Hence, we find that effected change in transfer and change in taxes are equal. It is due to fact that their size of changes as well as multiplier are equal.

Question 19.
What do you understand by Goods and Service Tax (G.S.T.)? How is G.S.T. better than old system of taxation? Explain its types.
Answer:
(a) The Goods and Services Tax (G.S.T.) is a value Added Tax (VAT) levied on most goods and services sold for domestic consumption. The G.S.T. is paid by consumers, but it is remitted to the government by the businesses selling the goods and services:

G.S.T. in comparison with old taxation system :

1. In place of old taxation system, G.S.T. will become one tax economy.
2. The tax structure will be simplified with G.S.T.
3. G.S.T. will save both time and money.
4. The growth rate of economy will show a rapid increase with G.S.T.
5. But for the time being, the G.S.T. would be expected to increase the inflation rate in comparison to the old tax system.

For Goods and Services Tax, G.S.T., U.T.G.S.T. Act and S.G.S.T. tax are passed.

Government Budget and Economy Long Answer Type Questions

Question 1.
Explain the types of budget.
Answer:
The types of budget are as follows :
1. Central budget:
Central budget is prepared by Central Government. It is the numerical statement of income and expenditure done by central government. In India Central budget is presented in two parts:

• General budget
• Railway budget.

2. State budget:
State budget is prepared by State Government. State Government takes the help from Central Government.

3. Revenue budget and Capital budget:
In revenue budget we include the expenditure and income related to revenue of the government. On the other hand in capital budget the capital expenditure and capital income is included.

4. Supplementary budget:
Supplementary budget is prepared for the temporary period. It is prepared during the period of emergency like flood, earthquake and war etc. There is no fixed time for it.

5. Balanced budget and Imbalanced budget:
Balance budget is that budget where income and expenditure of the government is equal. Imbalanced budget is that budget where expenditure is more or less than income of the government. If the expenditure is more than income it is called deficit budget and if the income is more than the expenditure it is called surplus budget.

Question 2.
Explain the procedure of the budget.
Answer:
Under the budgetary procedure in India we can study the following heads:

1. Preparation of budget : The preparation of budget involves the following steps :

• Sending estimate forms by finance minister to all ministers and their department’s heads to get the estimates of revenue and expenditure required for the next financial year.
• Preparation of estimates by departmental heads : It includes revenue and expenditure of previous year budgetary estimate for next coming year.
• Preparation of consolidated estimate by the various ministers and sending them to finance minister.
  Scruting report estimates by A.G. of India and sending the same to finance ministry.

2. Presentation of the budget : In India the budget is presented in two parts :

• General budget and
• Rail budget.

Rail budget is always present before the general budget. General budget presented on the last day of the month of February at 5 p.m. generally 28th in February.

3. Discussion on the budget:
Budget is put before the Parliament for discussion. In the processes of passing the budget, the discussions on various items continues for 3 – 4 days. Presently different committees are formed. For the discussion and finance minister gives his final reply on the budget.

4. Voting on budget:
After the general discussion the budget is put for voting. The members of parliament give their speeches for and against the budget before voting. There after voting is held for passing the budget.

5. Appropriation bill:
The finance minister presents appropriation bill. According to the constitution no amount from the Reserve fund of India can be withdrawn without passing the appropriation bill in the Parliament.

6. Financial bill:
All the financial proposals for the coming year are included in a bill which is known as financial bill. This bill is generally presented immediately after the presentation of budget in the Lok Sabha. If this bill is not passed by the Parliament f ur government L not supposed to spend any amount.

7. Vote on account:
Special arrangement is made under which special power is vested with Lok shabha to snetion some amount as advance till the final budget is passed for the next year.

8. Implementation of budget:
After the budget is passed, it is implemented by the government for which the following steps are taken :

• Collection of revenue
• Preparation of accounts in
• Audit by A.G. (Auditor General).

Audit by comptroller and Auditor General of India presents their report before the Parliament which comprise the receipt of revenue, expenditure, loans taken.

Question 3.
Write the tax revenue sources of Public Revenue:
Answer:
Following are the sources of Public Revenue :
Tax:
Taxes are neither a fees nor a penalty because it is neither taken by the government to give any additional benefits nor taken as a fine. Taxes are compulsory contribution which are given by the people to the government in order to meet the expenditure on the Welfare of the citizens.

Types of taxes : Taxes are of following types :

• Progressive tax – In progressive tax the rate of my increases as the income increases
• Proportional tax – Proportional taxes are those taxes whose impact and incidence falls equally on both the sections of the society.
• Regressive tax – The rate of taxation decreases with the increase in income. The burden of text falls more heavily on poor than on rich.
• Direct taxes – These are those taxes in which the impact of the tax and incidence of tax is on the same person.

Question 4.
What do you understand by Non – tax sources of public revenue?
Answer:
Following are the non – tax sources of public revenue:

1. Fees, licence and permit:
Government gets non – tax revenue from fees licence fee and payment made for permits.

Fees – Registration fee for land, death and birth registration fees, passport fees are included in it.

Licence and permit – Fee is that fee which is paid by people to government after giving permission by the government to the people to do something. For example: Driving licence, import licence etc.

2. Fines:
Fines are collected by the govt, for breaking rules of the country. The main aim of this is not to collect money but to teach people lesson about it.

3. Income from public enterprise: Government may raise funds from many sources like Railways, Postal department, Steel Plants fertilizer Corporations, Indian Oil department etc. Government sells products of it and gets profit from it.

4. Gifts and grants: The government may raise the funds from others. During calamities like flood, earthquake etc. citizens and some NGO’s give help to the government . For example : W.H.O., UNESCO etc. they give assistant also during this period.

5. Notes issues:
Sometimes government prints extra notes and increase the treasury. Reserve Bank of India has got the right of printing notes and minting coins.

6. Stamp, registration and land revenue: The receipts of stamps, registration and land revenue is the another source of non – tax revenue. The stamp receipts of Supreme court is also the income of the central government.

7. Interest, receipts : Interest earned by  the government from the loans given to States, Union territories. Railways, Post and Telegraph are included in it.

8. Dividends: This includes the share from profits of various undertakings in which the central government has done investments example SAIL, ONGC etc.

9. Administrative receipts:
The central government provides a number of services to people like health, medical, education etc. The government earns certain income from these services. For example; court fees, registration fees.

Question 5.
Consider an economy described by the following functions. C = 20 + 0.80 Y, I = 30, G = 50, TR = 100.
(a) Find the equilibrium level of income and the autonomous expenditure multiplier in the model,
(b) If the government expenditure increases by 30, what is the impact on equilibrium income?
(c) If a lump sum tax of 30 added to pay for increase in government purchases, how will equilibrium income change?
Answer:
C = 20 + 0.80y
I = 30
G = 50
TR = 100
(a)
Y = \(\overline { C } \) + CY – (T – TR)
Y = 20 + 0.80 (Y + TR) + I + G
Y = 20 + 0.80 (Y + 100) + 30 + 50
Y = 0.8Y + 180
Y = \(\frac {180×100}{200}\)
= 900
The equilibrium level of income is 900. Autonomous expenditure multiplier.
= \(\frac {1}{1 – C}\)
= \(\frac {1}{1-0.08}\)
= \(\frac {1}{0.20}\)
= 5
Increase in equilibrium income = AG x Expenditure multiplier = 30 x 5 = 150
Tax multiplier = \(\frac {-C}{1 – C}\) = \(\frac {-0.08}{1-0.08}\) = \(\frac {-80}{0-20}\) = -4
Decrease in equilibrium income = ∆T x Tax Multiplier
= 30 x 4 = 120.
or
Y = \(\frac {1}{0.20}\)(180)
Y = 5 x 180 = 900
autonomus multiplier \(\frac { ∆Y}{∆G}\)= \(\frac {1}{1 – C}\)
or
\(\frac { ∆Y}{∆G}\) = \(\frac {1}{1-0.80}\) = \(\frac {1}{0.20}\) = 5

(b) Expenditure of govt, increase by 30 :
(∆Y) = \(\frac {1}{1 – C}\) ∆G
or
∆Y = \(\frac {1}{1-0.80}\) x 30
= \(\frac {1}{0.20}\) x 30 = 5 x30 = 150
New income = 900 + 150 = 1,050
So, it is clear that by 30 it become 150 to 1,050.

(c) Lump sum 30 is added then :
Change in balance income (∆Y) = \(\frac {-C}{1 – C}\) ∆T
or
∆Y = \(\frac {-0.08}{1-0.08}\) x 30
= \(\frac {-0.08}{0.20}\) x 30 = -4 x 30
= 1 – 120
= 900 – 120 = 780

MP Board Class 12th Economics Important Questions

MP Board Class 12th Economics Important Questions Unit 8 Money and Banking

Micro Economics Money and Banking Important Questions

Micro Economics Money and Banking Objective Type Questions

Question 1.
Choose the correct answers:

Question 1.
“Money is what money does”. Who said this:
(a) Hartley Withers
(b) Harte
(c) Prof. Thomas
(d) Keynes.
Answer:
(a) Hartley Withers

Question 2.
Function of money is:
(a) Medium of exchange
(b) Measure of value
(c) Store of value
(d) All of the above.
Answer:
(a) Medium of exchange

Question 3.
Meaning of money supply is:
(a) Money deposits in the bank
(b) Cash available with public
(c) Savings in the post office
(d) All of the above.
Answer:
(d) All of the above.

Question 4.
What is the Central Bank of India:
(a) Commercial Banks
(b) Central Bank
(c) Private Bank
(d) None of these.
Answer:
(a) Commercial Banks

Question 5.
Through which method we can withdraw money from the bank:
(a) Drawing letter
(b) Cheque
(c) A.T.M.
(d) All of the above.
Answer:
(d) All of the above.

Question 6.
Who is the guardian of Indian Banking System:
(a) Reserve Bank of India
(b) State Bank of India
(c) Unit Trust of India
(d) Life Insurance Company of India.
Answer:
(a) Reserve Bank of India

Question 7.
Narasimham Committee is related to what:
(a) Improvement in Taxation
(b) Improvement in Banking
(c) Improvement in Agriculture
(d) Improvement in Infrastructure.
Answer:
(b) Improvement in Banking

Question 2.
Fill in the blanks:

1. Central Bank of India is………………..
2. Bank rate is also known as………………..
3. The bank generates……………….. deposits in credit creation.
4. When CRR decreases, credit creation………………..
5. Measure of deferred payment is ……………….. function of money.
6. Medium of exchange is ……………….. function of money.
7. The static and dynamic function of money is divided by………………..

Answer

1. Reserve Bank of India
2. Redemption
3. Derivative
4. Increases
5. Secondary
6. Primary
7. Paul Einzig.

Question 3.
State true or false:

1. Money is needed for day-to-day transactions.
2. The precautionary demand for money increases with the proportionate increase in income.
3. Reserve Bank of India provides loan to public.
4. Along with the Reserve Bank of India, Commercial banks are also authorized to issue currency.
5. Reliable money also include cheques.
6. Reserve Bank of India cannot become the owner of any real estate.

Answer:

1. True
2. True
3. False
4. False
5. False
6. True.

Question 4.
Match the following:

Question 5.
Answer the following in one word / sentence:

1. Name the bank that provides long term loans to the farmers.
2. Trade cycle is which evil of money?
3. By increasing liquid fund ratio, which will be the effect on money supply?
4. “The Banks are not only generators of money but are also creators of money”.
5. Who has the right to issues paper money?
6. When was NABARD established?

Answer:

1. Agricultural or Cooperative banks
2. Economic
3. Decreases
4. Sayer’s
5. Central Bank
6. 1982.

Micro Economics Money and Banking Very Short Answer Type Questions

Question 1.
Write two taboo works of Reserve Bank of India.
Answer:
Two taboo works of RBI are:

1. Reserve Bank cannot accept deposits on interest from the public.
2. Reserve Bank cannot provide loans for a fixed term.

Question 2.
What do you mean by overdraft facility?
Answer:
Clients who have current account with the bank are granted” the facility of withdrawing more money than actually lying in their accounts. It is called overdraft. This facility is available to reliable person for a short term.

Question 3.
What is commercial bank?
Answer:
Commercial banks are those banks who are established under the Indian Company Act, and they perform all the functions of banks.

Question 4.
Write the meaning of money.
Answer:
According to Prof. J.M. Keynes, Money is that by the delivery of which debt contracts and price contracts are discharged and in the shape of which a store of general purchasing power is held.

Question 5.
Write any two economic defects of Money.
Answer:
Two economic defects of money are:

1. Money gives birth to trade cycle.
2. Currency is the trust worthy custodian of money.

Question 6.
When was Reserve Bank of India nationalised?
Answer:
Reserve Bank of India was nationalised on 1st January 1949.

Question 7.
Which is the Central Bank of India? When was it established?
Answer:
Central Bank of India is Reserve Bank of India. It was established on 1st April, 1935.

Question 8.
What do you mean by Bank?
Answer:
Nowadays, the word ‘Bank’ is very common and popular so, general public is acquainted with it. Generally, bank means that institution which deals with transactions of money.

According to Prof. Wicksell:
“Bank is the heart and central point of modem currency system”.

Question 9.
Write definitions of money.
Answer:
According to Prof. Hartley Withers, “Money is what money does”. According to Prof. Seligman, “Money is one thing that possesses general acceptability”.

Question 10.
What is the problem of double coincidence of wants in barter exchange?
Answer:
1. Problem of double coincidence:
In barter system, goods are to be exchanged for goods, hence, it is essential that both the parties should need the goods which other has in exchange of their goods, then only the exchange is possible.

2. For example, ‘A’ possesses a chair and ‘B’ possesses a table. Now if ‘A’ wants to exchange his change for a table then he has to search a person, who needs chair in exchange of table. Thus, becomes a complex process for him to find such man.

Question 11.
‘Money is the medium of exchange,’ Explain.
Answer:
Medium of exchange:
This is the most important function of money. It acts as a medium of exchange. All the exchanges of goods and services are taken place in terms of money. (MPBoardSolutions.com) By paying predetermined price, money can be exchanged with the desired goods and services. A money has the general acceptability, therefore, all the exchanges in an economy take place in terms of money. It is because of this reason that money has been defined as generally acceptable purchasing power.

Question 12.
“Measure of value is the main function of money”. Explain.
Answer:
“Measure of value is the main function of money”:
The main function of money is that it measures the value of goods and services. In other words, the prices of all goods and services are expressed in terms of money. In ancient times it was not possible to measure the value of clothes and wheat. With the introduction of money, this difficulty of measurement disappeared and it became very convinient to measure the value of money. Money acts as a unit of account for all goods, wages salaries, interests etc. The national income, capital formation and other are measured in terms of money.

Question 13.
Write the importance of the money as the store of exchange value.
Answer:
Money acts also as a store of value because:

1. Money can be stored very easily. Money is a liquid form of capital. It require less place to store.
2. Money has the merit of general acceptibility.
3. It is convinient to store money.
4. Value of money remains relatively stable. Due to all these reasons money is important.

Question 14.
What is meant by money supply? What are its measures?
Answer:
Money supply refers to the total volume of money held by the public at a particular point of time in an economy.
Measures of money supply are:
M₁ = Currency and coins with public + Demand deposits of Commercial banks + Other Deposites with RBI.
M₂ = M₁ + Savings deposits with post office Saving bank.
M₃ = M₂ + Net time deposits with banks.
M₄ = M₃ + Total deposits with post office saving bank.

Question 15.
Write difference between Scheduled Banks and Non – Scheduled Banks.
Answer:
Differences between Scheduled Banks and Non – Scheduled Banks:

Scheduled Banks:

• Scheduled banks are those banks whose names appear in the second schedule of RBI.
• The paid up share capital together with reserve fund must not be less than Rs. 5 lake.

Non-Scheduled Banks:

• Non – scheduled banks are those banks whose names do not appear in the second schedule of RBI.
• The paid up capital of such banks together with cash reserve is less than Rs. 5 lake.

Question 16.
If in an economy, all the customers of the bank deposit their money in the banks and if all of them withdraw their money from the bank then what will be its effect on the economy?
Answer:
If in any economy, bank customers deposit their money in the banks then there will be shortage of money for production and investment activity. As a result, the process of development will come to a stand still. In the same way, if all the customers withdraw their money from the banks, the banking would collapse and economy will face a problem. If in any bank financial crisis arises then central bank is the only bank to settle this problem and all banking systems will collapse.

Question 17,
Write the meaning of Commercial banks?
Answer:
A commercial bank is a financial institution which accepts deposits from the public and gives loans for purposes of consumptions and investment.

Companies Act, 1949:
A banking company is one which transacts the business of banking which means the accepting for the purpose of lending or investment of deposits of money from the public repayable on demand or otherwise and withdrawal by cheque or otherwise.

Question 18.
Write the types of Commercial bank.
Answer:
There are two types of Commercial banks:

1. Scheduled banks:
Scheduled banks are those banks whose names appear in the second schedule of RBI.

2. Non – scheduled banks:
Non – Scheduled banks are those, banks whose names do not appear in the second schedule of RBI. In other words, those banks which do not fulfill the requisite conditions as explained above are called non-scheduled banks.

Question 19.
What is paper money?
Answer:
Paper money is a country’s official paper currency that is circulated for transaction related purposes of goods and services. The printing of paper money is typically regulated by a country’s Central bank / treasury in order to keep the flow of funds in line with monetary policy.

Paper money is that money which is issued by the order of the government. Paper money is in the form of paper notes or currency notes. In India, the Reserve Bank of India enjoys the sole monopoly of issuing currency notes (Paper money).

Question 20.
What do you mean by money supply?
Answer:
Supply of money is a stock concept. It refers to total stock of money (of all types) held by the people of a country at a point of time.

Question 21.
What do you mean by Fiat money or Legal tender money?
Answer:
Fiat money which serves as money on the basis of fiat (order) of the government It is issued by authority of the government. It includes notes, coins.

Question 22.
What do you mean by C.R.R.?
Answer:
Commercial banks are required under law to keep a certain percentage of their total deposit in the Central bank in the form of cash reserves. This is called Cash Reserve Ratio (C.R.R.).

Question 23.
What do you mean by credit money?
Answer:
It refers to that money of which money value is more than commodity value.

Question 24.
Why is paper money called the Legal tender money?
Answer:
Paper money or Paper notes are called as legal tender money because nobody can refuse its acceptance as medium of exchange. It is legal tender. It means people have to accept it legally for different payments.

Question 25.
What do you mean by high powered money?
Answer:
It consist of currency (Notes and Coins in circulation with public and valt cash of commercial banks) and deposits held by the government of India and commercial banks with R.B.I.

Micro Economics Money and Banking Short Answer Type Questions

Question 1.
“Money is a good servant but a bad master”. Explain.
Answer:
Money is becoming essential part of life, it is controlling our activities in such a way that we are completely under it. It should be means but is has become end of life. Till money acts as servant it is useful for human being but as money goes out of control it becomes harmful for the entire economy. This situation arises when supply of money exceeds its demand. Money becomes master instead of servant. It has become the only means of satisfying our wants. We cannot think of our life without money that is why, it is said that “money is good servant but a bad master.”

Question 2.
Define Central bank.
Answer:
Central bank of any country is the highest financial institution of that country. All other banks of the country work under its guidance. According to bank of international settlements. “The central bank in any country is that which has been entrusted the duty of regulating the volume of currency and credit in the country”.

Question 3.
What do you mean by clearing house of Central bank?
or
How Central bank does the work of clearing house?
Answer:
Clearing house:
Representatives of different banks in a city meet at the clearing house of the Central bank. Payments from one bank to other bank are settled through a simple book of adjustments without involving transfers of funds. Daily differences in the clearing between the banks are adjusted by means of debit and credit entries in their respective account with the Central bank.

Question 4.
Write two advantages and defects of Commercial banks.
Answer:
Following are the two advantages of commercial banks:

1. Use of savings for production purposes:
Banks collects small and big savings of the country and use them for various purposes. Banks provide timely financial assistance to traders and industries. Banks help in the distribution of surplus capital in regions where it is not wanted to those regions where it can be used. Large scale transactions would be quite impossible without banks.

2. Facility of capital transfer:
Banks spend money from one place to another easily in less time. They send it through draft, cheques, etc. For the development economy money can be transferred from one place to another.

Defects of commercial banks:

1. Less banking facilities:
Compare to other countries there are less banking facilities available in India.
Some banks do not get proper guidance and instructions from reserve bank of India. It has unfavourable effect on banking system. So, Indian Commercial banking system has not succeeded in attracking the Indian public.

2. Inefficiency:
Most of the commercial banking systems are unable to provide efficient and quick services to their customers. Moreover in India the distribution of commercial banks are in imbalance way.

Question 5.
Differentiate between Reserve Bank and Commercial Bank.
Answer:
Differences between Reserve Bank and Commercial Bank:

Reserve Bank:

• It is the highest bank of India. It is a controlling bank.
• There is only one central bank (Reserve bank) in India.
• It enjoys the monopoly right for note issue.
• It has no dealing and direct relation with public.
• The ownership of this bank is in the hands of central government.

Commercial Bank:

• It is a part of banking system. It is con trolled by Reserve Bank of India.
• There are many commercial banks in India.
• A commercial bank does not have such right.
• It has direct relation and dealing with public.
• The ownership of this bank is in the hands of government or public.

Question 6.
Why is speculative demand for money inversely related to the rate of interest?
Answer:
Speculative demand for money is made for return in the form of interest. Hence, rate of interest determiners the speculative demand for money of the rate of interest higher the speculative demand for money will be low and vice-versa. The reason is that people will convert their money in bonds when the interest on bond is higher.

In that case, demand for speculative purpose will be low. On the other hand, the rate of interest is lower than the expected interest, people will not convert their money in bonds and keep money in hand for speculative purpose. In this way, a specular demand for money in inversely related to the of interest.

Question 7.
What role of RBI is known as lender of last resort?
Answer:
Lender of last resort:
The Central Bank aslo plays the role of last resort. Lender of last resort means that a Commercial Bank fails to meet his financial requirements from other sources, it can as a last resort, approaches to the Central Bank for loans and advances. The Central Bank consists such bank through discounting of approved securities and bills of exchange. As a last resort, Central Bank exercise control over the entire banking system of the conuntry.

Question 8.
What is liquidity trap?
Answer:
Liquidity Trap:
Everyone in the economy holds his wealth in money balance and if additional money is injected within the economy, it will be used to satiate people’s craving for money balances without increasing the demand for bond and without further lowering the rate of interest below the flow min. Such a situation is called liquidity trap.

Question 9.
What is barter system? What are its defects?
Answer:
Barter system:
Barter system means the exchange of goods and services directly for goods and services. In other words economic exchange without the medium of money is referred to as Barter system.

Drawbacks of barter system : Following are main drawbacks of the barter system:

1. Lack of double coincidence:
The lack of double coincidence of wants is the major drawback. It is very rare when the owner of same goods or service could find some are who wants his good or service and possessed that good service that the first person wanted. No exchange is possible if the double coincidence is not there.

2. Absence of common unit of measurement:
The second main drawback of barter is the absence of a common unit of measurement in which the value of goods and services can be measured. In the absence of a common unit proper accounting system is not possible.

3. Lacks of standard deferred payments:
Thirdly, the barter system lacks any satisfactory unit to engage in contracts involving future payments. In a barter economy future payments would have to be stated in specific goods of services which may involve disagreement over the quality of goods or even on the commodity used for repayment.

4. Lack of storing wealth:
Fourthly, the barter system does not provide for any method of storing purchasing power.

Question 10.
Suppose a bond promises Rs 500 at the end of two years with no intermediate return. If the rate of interest is 5% per annum, what is the price of the bond?
Answer:
= 500 x \(\frac { 1 }{ \left\lceil 1+\frac { 5 }{ 100 } \right\rceil \left\lceil 1+\frac { 5 }{ 100 } \right\rceil } \)
= 500 x \(\frac { 20 }{ 21 }\) x \(\frac { 20 }{ 21 }\)
=\(\frac { 10,000 x 20 }{ 21 x 21 }\)
=\(\frac { 2,00,000}{ 441 }\)
= Rs 453.51.

Micro Economics Money and Banking Long Answer Type Questions

Question 1
What do you mean by stock of money and flow of money?
or
Write the differences between the stock of money and flow of money.
Answer:
Differences between Stock of money and Flow of money:

Stock:

• Stock is related to a point of time.
• A stock is a quantity measurable at a particular point of time such as 10:00 am etc.
• It has no time dimension.
• National capital is stock.
• It is a static concept.

Flow:

• Flow is related to a period of time.
• A flow is a quantity which is measured over a specific period of time such as an hour, a day, a week etc.
• It has time dimension.
• National income is a flow.
• It is a dynamic concept.

Question 2.
Explain five functions of RBI in detail.
Answer:
Followings are the functions of Reserve Bank of India:

1. Issue of currency notes:
The Reserve Bank of India has been given the monopoly of issuing currency notes. At present, it is authorised to issue currency notes in the denomination of Rs. 5,10,20,50,100,500 and 2,000. One rupee note and coins are issued by government of India. The notes issued by R.B.I. are legal currency.

2. Credit control:
The main functions of R.B.I. is to control and regulate volume of credit and currency in India. It controls the credit granted by commercial banks. It controls the credit inflationary impact of the ever increasing development financing in five year plans. R.B.I. controls the credit by increasing or decreasing bank rates buying and selling government securities in the open market, by increasing the cash reserves, by issuing specific directions to banks etc.

3. Banker agent and advisor to government:
The reserve bank of India acts as banker, agent and advisor to the central and state governments. As a banker to government R.B.I. performs many functions. It manages the public debt, makes all payments, receives all the revenues in government account managing foreign exchange, etc. R.B.I. has appointed experts of all fields of specialization who gives proper advice to central and state governments in various matters from time-to-time.

4. Banker’s bank:
R.B.I. is banker to banks in India. It accepts deposits of commercial banks and lends of them from time – to – time. It extends short term loans and advances against eligible securities and promissory notes. It makes purchases and sales of foreign currencies also. The commercial and other banks have to deposit with R.B.I. a certain percentage of their total liabilities to enjoy various facilities from it.

5. Foreign exchange management:
R.B.I. controls all receipts and payments in foreign exchange under F.E.M. A. All payments to be made in foreign exchange exceeding the limit prescribed under the act must seek RBI’s permission.

Question 3.
Explain the methods to control the credit taken by the reserve bank.
Or
Explain how the Reserve Bank of India controls credit.
Answer:
Followings are the methods to control the credit:

1. Bank rate:
The rate at which Reserve Bank of India gives loan to other banks on the basis of securities is called bank rate. R.B.I. increases or decrease the bank rate for reducing or expanding the credit from time-to-time.

2. Activities of open market:
R.B.I. buys and sells the government securities in the open market for expanding and reducing the volume of credit. This is called open market operation. By this activities R.B.I. increases or decreases the amount of money.

3. Changing the ratio of bank’s reserves:
R.B. I. controls the credit by increasing the percentage of cash reserves which is kept by scheduled commercial banks compulsorily with R.B.I.

4. Liquidity ratio-system:
Reserve Bank of India increases or decreases the liquidity ratio for reducing or expanding credit.

5. Selective credit control policy:
Reserve bank adopts the selective credit control policy in respect of certain commodities which have been sensitive.

6. By issuing specific directions to banks:
R.B.I. issues specific directions to banks in general regarding lending rates.

7. Increase or Decrease refinancing facility:
R.B.I. increases or decreases refinancing facility to commercial banks for credit control. Rigid attitude for refinancing reduces credit and liberal attitude for refinancing expands credit.

Question 4.
Suggest some measures to remove the defects of commercial bank.
Answer:
Following steps should be taken to improve the conditions of Indian commercial banks:

1. For the balance development of commercial banks their new branches should be open in villages and backward areas.
2. To solve the problem of shortage of capital the money deposits schemes of the banks should be made attractive.
3. Knowledge and education regarding the banks should be given clearly.
4. For increasing the banking systems the trained and efficient officers should be appointed.
5. Reserve bank should make such rules which will control the corruption in the banking system.
6. Banks should follow the policy of cooperation with other banks instead of following the policy of competition with each other.

Question 5.
Write any five functions of Commercial Banks.
Answer:
Following are the functions of Commercial banks:

I. Primary Functions

1. Acceptance of deposits:
All commercial banks accept money on deposits. By taking money on deposits a bank provides safe keeping for people’s money. For deposition of money a bank provides facility of five types of customer accounts:

• Current account
• Fixed deposit account
• Savings bank account
• Home savings account and
• Recurring deposit account.

2. Lending and Investment:
The second primary function of a bank is to lend money to borrowers bank keeps a part of the total deposits with itself as cash reserves and lends the balance. Bank charges interest on such lending of money, which is also the main source of profit to most of the banks. Money lending may be in the form of overdrafts, cash credits or loans.

II. Subsidiary Functions

In order to provide several kinds of facilities to their customers commercial banks perform many functions. They are as follows:

1. Issuing of credit instruments:
All commercial banks issue various instruments of credit such as bill of exchange, hundi, draft and cheque etc.

2. Arrangement of foreign exchange:
For foreign trade banks convert the currency of one country into the currency of another country. This work is done by exchange Banks.

3. Keeping valuables safely:
Banks provide the facility of lockers for the customers to keep their valuable things gold, diamonds, Jewellary etc. are kept in these lockers.

4. Discounting of bills of exchange and hundies:
Banks discount the bill and hundies of their customers before the date of maturity of such instruments.

5. Collecting payments:
Commercial banks collect payments of their customers bills, cheques and hundies etc. Banks charge commissions for these services.

6. Making payments:
Banks make payments on behalf of their customers. The make payments of installments of loans, interest, donations, insurance etc.They charge nominal commission for their services.

7. Selling and Purchasing of securities:
Commercial banks sell and purchase shares, debentures Govt.bonds etc.

Question 6.
What are the main functions of money? How does money remove the defect of barter system?
Answer:
Followings are the functions of money:

Primary Functions:

1. Medium of exchange:
This is the most important function of money. It acts as a medium of exchange. All the exchanges of goods and services are taken place in terms of money. By paying predetermined price, money can be exchanged with the desired goods and services.

2. Measure of value:
The second basic function of money is that it measures the value of goods and services. In other words, the prices of all goods and services are expressed in terms of money. In ancient times it was not possible of measure the value of clothes and wheat. With the introduction of money this difficulty of measurement disappeared and it became very convinient to measure the value of money. Money acts as a unit of account for all goods, wages salaries, interests etc. The national income, capital formation and other are measured in terms of money.

3. Store of exchange value:
Money can be stored very easily. Money is a liquid form of capital. It require less place to store. There is very less fluctuation in the value of money in comparison to goods. That is why mentry to save a part of their income for future. Money provides a base for store value.

Store of value means store of wealth.People can now keep their wealth in the form of money. Under barter system, storing of wealth was possible only in terms of commodities which had its defects like perishable nature of some goods, cost of storage etc. But storing of value in the form of money has solved all these difficulties. It was Keynes who first realised the store value function of money. He regarded money as link between the present and the future. Money allows us to store purchasing power which can be used at any time in future to purchase goods and services.

4. Transfer of value:
With the economic development the trade and commerce also increased rapidly. This causes the need of transfer of money from one place to another. Sometimes it crosses the national boundary too. Money is a liquid assets so it can be transferred from one place to another.

Through money, value can be easily and quickly transferred from one place to another because money is acceptable everywhere. For example a person can transfer money from Katakana to Delhi through bank draft, bill of exchange etc. Money thus, facilitates movement of wealth and capital. Under barter system it was difficult to transfer value in the from commodities.

Question 7.
Explain the functions of commercial banks. (Any two)
Answer:
Functions of a Commercial Bank:
Following are main functions of a commercial Bank:

1. Acceptance of deposits:
This is an important primary function of the Commercial Banks. The Commercial Banks accept deposits from individuals, business firms and other institutions. This is economically useful function in the sense that it helps in the mobilization of savings for production purposes. The commercial banks accept deposits in several forms according to the requirements of different sections of the society.

2. Advancing of Loans:
Extending loans is another important primary function of the commercial banks. It is also the main source of their income. Traditionally, bankers charged a service charge from the depositors, as they did not use the deposits for lending purposes. Gradually, they realized that.there is no point in keeping all the money which they received from depositors as revenue. All the depositors never approached bankers to withdraw their money at one point of time. In the beginning, their lending out of deposits were confined to short term loans to provide working funds for current business operations.

Now, banks have extended their lending activities to investment in long term bonds. Furthermore, today, commercial banks lend to consumers and government units besides financing trade and industry to meet the divergent needs of their customers. In the manner, they could find safe and lucrative outlets for their funds. The normal performance for banks is for secured loans, but they often give loans to business firms of high credit standing without security. .

Question 8.
What is money multiplier? How will you determine its value?
Answer:
Money multiplier:
Money multiplier may be defined as “the ratio of the stock of money to the stock of high powered money in an economy.” In equation:
Money multiplier = \({ M }{ H }\)
M = Stock of money
H = Stock of high powered money in an economy
The value of money multiplier is greater than 1. The value of money multiplier is determined by applying the following formula:
Money multiplier = \({ 1- cdr }{ cdr – rdr }\)
Method of finding out multiplier
Supply of money = Money + Deposit
M = Cu + DD
= (1 + Cdr) DD
Cdr = Cu / DD
H = Cu + R
= CdrDD + rdr DD
= (Cdr + rdr) DD
Money multiplier = M/H
\(\frac { (1+Cdr)DD }{ (Cdr+rdr)DD }\) = \(\frac { 1+Cdr }{ Cdr+rdr }\)
1 + Cdr > Cdr + rdr.

Question 9.
What are the methods adopted by Reserve Bank of India to regulate the credit?
Answer:
There are those instruments of monetary policy which after overall supply of money / credit in the economy. They are as follows:

1. Bank Rate:
The bank rate is the minimum rate at which the Central Bank of a country (as a lender of last season) is prepared to give credit to the Commercial Bank. The increase in bank rate increases the rate of interest and credit becomes dear. Accordingly, the demand for credit is reduced. On the other hand, decrease in the bank rate lowers the market rate of interest charged by the commercial banks from their borrowers. Credit becomes cheap. The Reserve Bank adopts dear money policy when the supply of credit needs to be reduced during periods of inflation. It adopts cheap money policy when credit needs to be expanded during deflation.

2. Open Market Operations:
Open Market Operations refer to the sale and purchase of securities in the open market by the Central Bank. By selling the securities (like, National Saving Certificates-NSCs), the Central Bank withdraws cash balances from within the economy. And, by buying the securities, the Central Bank contributes to cash balances in the economy.

3. Cash Reserve Ratio (CRR):
It refers to the minimum percentage of a bank’s total deposits required to be keep with the Central Banks. Commercial Banks have to keep with toe Central Bank a certain percentage of their deposits in the form of cash reserves as a matter of law. When the cash flow or credit is to be increased, minimum reserve ratio is reduced and when the cash flow or credit is to be reduced, minimum cash reserve ratio is increased.

4. Statutory Liquidity Ratio (SLR):
Every bank is required to maintain a fixed percentage of its assets in the form of cash or other liquid assets, called SLR. With a view to reducing the flow of credit in the market, the Central Bank increases this liquidity ratio. However, in case of expansion of credit, the liquidity ratio is reduced.

Qualitative Method of Credit Control
Or
Qualitative Instruments of Monetary Policy

1. Margin Requirement:
The margin requirement of loan refers to the difference between the current value of the security offered for loans and the value of loans granted. Suppose, a person mortgages an article worth Rs 100 with the bank and the bank gives him loan of Rs 80. The margin requirement in this case would be 20 percent. In case, the flow of credit is to be restricted for certain specific business activities in the economy, the margin requirement of loan is raised for those very activities. The margin requirement is lowered in case the expansion of credit is desired.

2, Rationing of Credit:
Rationing of credit refers to fixation of credit quotas for different business activities. Rationing of credit is introduced when the flow of credit is to be checked particularly for speculative activities in the economy. The Central Bank fixes credit quota for different business activities. The Commercial Banks cannot exceed the quota limits while granting loans.

MP Board Class 12th Economics Important Questions

MP Board Class 12th Physics Important Questions Chapter 3 Current Electricity

Current Electricity Important Questions

Current Electricity Objective Type Questions

Question 1.
Choose the correct answer of the following:

Question 1.
The flow of current through a conduction is due to:
(a) Protons
(b) Positive ions
(c) Free electrons
(d) Positive and negative ions.
Answer:
(c) Free electrons

Question 2.
The specific resistance of a wire depends upon:
(a) Length
(b) Diameter
(c) Mass
(d) Material.
Answer:
(b) Diameter

Question 3.
A wire is stretched redouble its length. Its resistance will be:
(a) Halved
(b) Doubled
(c) One fourth
(d) Four times.
Answer:
(d) Four times.

Question 4.
The unit of specific resistance is :
(a) Ohm
(b) Ohm^-1
(c) Ohm meter
(d) Ohm^-1
Answer:
(c) Ohm meter

Question 5.
Which of the following is an oh-mic resistance:
(a) Junction transistor
(b) Transistor
(c) LED
(d) Copper wire.
Answer:
(d) Copper wire.

Question 6.
On increasing temperature the resistance of the which of the following decreases :
(a) Semiconductor
(b) Metal
(c) Electrolyte
(d) Alloy.
Answer:
(a) Semiconductor

Question 7.
The conductance of super conductor is :
(a) Infinite
(b) Very high
(c) Very low
(d) Zero.
Answer:
(a) Infinite

Question 8.
In the series combination of two resistance which quantity remains same :
(a) Only potential difference
(b) Only current
(c) Current and potential difference both
(d) Neither current nor potential difference.
Answer:
(b) Only current

Question 9.
Electric cell is source of:
(a) Electrons
(b) Electrical energy
(c) Electric charge
(d) Electric current.
Answer:
(b) Electrical energy

Question 10.
The e.m.f. of a cell depends upon:
(a) Quantity of electrolyte filled in it
(b) Distance between the electrodes
(c) Size of electrodes
(d) Nature of electrolyte and electrodes.
Answer:
(d) Nature of electrolyte and electrodes.

Question 11.
Three cells each having e.m.f. E and internal resistance r are joined in series. One cell by mistake is joined in reverse order. The resultant e.m.f. and internal resistance will be:
(a) 3E, 3r
(b) E,3r
(c) E, r
(d) 3E,r
Answer:
(b) E,3r

Question 12.
The internal resistance of a cell can be decreased by :
(a) Decreasing the size of electrodes
(b) Increasing the distance between electrodes
(c) Decreasing the distance between electrodes
(d) None of these.
Answer:
(c) Decreasing the distance between electrodes

Question 13.
Two cells of e.m.f. and internal resistance E₁r₁ and E₂, r₂ respectively are joined in parallel. Their equivalent e.m.f. will be:
(a) E₁ + E₂
(b) E₁ – E₂
(c) \(\frac{\mathrm{E}_{1} r_{2}+\mathrm{E}_{2} r}{r_{1}+r_{2}}\)

(d) \(\frac{\mathrm{E}_{1}+\mathrm{E}_{2}}{r_{1}+r_{2}} \times r_{1} \cdot r_{2}\)
Answer:

(c) \(\frac{\mathrm{E}_{1} r_{2}+\mathrm{E}_{2} r}{r_{1}+r_{2}}\)

Question 14.
Potentiometer measures:
(a) Terminal voltage of cell
(b) Current in circuit
(c) e.m.f. of cell
(d) None of these.
Answer:
(c) e.m.f. of cell

Question 15.
In the null deflection position:
(a) No current flows through the galvanometer
(b) Current flows due to primary circuit through the galvanometer
(c) Current flows through galvanometer due to secondary circuit
(d) Nothing can be said.
Answer:
(a) No current flows through the galvanometer

Question 16.
The SI unit of the potential gradient is:
(a) ohm/cm
(b) volt
(c) volt cm
(d) volt/cm.
Answer:
(d) volt/cm.

Question 17.
To increase the sensitivity of potentiometer:
(a) The potential difference across its wire should be high
(b) The length of its wire should be less
(c) The current through the wire should be high
(d) potential difference across its wire should be low and length of wire should be large.
Answer:
(d) potential difference across its wire should be low and length of wire should be large.

Question 18.
In the balance condition of potentiometer its resistance is :
(a) Zero
(b) Infinite
(c) Very small
(d) Very high.
Answer:
(d) Very high.

Question 2.
Fill in the blanks:

1. According to ……….. law, a if the physical conditions of a conductor remains unchanged then current flowing through it is directly proportional to the applied potential difference.
2. On increasing the length of a conductor its resistance ………..
3. On decreasing the area of cross-section of a conductor its resistance ………..
4. On increasing the temperature of a metallic conductor its resistance ………..
5. KirchhofFs first law is in accordance with the law of conservation of ………..
6. In series grouping of resistors the resistance but in parallel grouping the resistance ………..
7. With increase in length of potentiometer its sensitivity ………..
8. Meter bridge works on the principle of ………..
9. The specific resistance of alloys is ……….. and temperature coefficient of resistance is ………..
10. The Kirchhoff’s first law is in accordance with the law of conservation of ……….. while the second law is in accordance with law of conservation of ………..
11. On increasing the distance between electrodes of a cell, its internal resistance ……….. but on increasing area its internal resistance ………..
12. The phenomenon in which at low temperature the resistivity of a substance becomes zero is celled ………..
13. In Ohm’s law the V-I graph is a ………..

Answers:

1. Ohm’s
2. Increases
3. Increases
4. Increases
5. Charge
6. Increases, decreases,
7. Increases
8. Wheatstone bridge
9. High, low
10. Charge, energy
11. Increases, decreases
12. Super conductivity
13. Straight line.

Question 3.
Match the Column:

Answer:

1. (e) Metre Bridge
2. (c) Law of conservation of charge
3. (b) Ohmic conductor
4. (a) Law of energy conservation
5. (d) Non-ohmic conductor

Answers:

1. (e) coulomb/sec. (or ampere).
2. (d) ampere/metre²
3. (b) joule/coulombx ampere
4. (c) ohm x meter
5. (a) ohm^-1

Answers:

1. (e) I²Rt
2. (a) ohm
3. (b) volt
4. (c) Electrical energy
5. (d) VI

Answer:

1. (c) Potential difference
2. (e) e.m.f.
3. (b) Vector quantity
4. (a) l₁/l₂
5. (d) \(\mathrm{R}\left(\frac{l_{1}}{l_{2}}-1\right)\)

Question 4.
Write the answer in one word / sentence:

1. What is the direction of electric current ?
2. What is the unit of specific resistance ?
3. Kirchhoffs first law is based upon which law ?
4. Kirchhoffs second law is based upon which law ?
5. On which principle does f&etre bridge works ?
6. Does Kirchhoffs law can be applied for both a.c. and d.c. currents ?
7. In a carbon resistance, there is green, violet, red and silver strip’s. What will be the resultant resistance.
8. What is the relation between 1 kWh and joule.
9. When the potentiometer is in equilibrium, what will be its resistance ?
10. The algebraic sum of current at a point is zero. Then what will be that point ?

Answer:

1. Opposite to flow of electrons,
2. Unit is ohm x meter
3. Laws of conservation of charges
4. Laws of conservation of energy
5. Wheatstone bridge
6. Yes
7. 57 x 10² ± 10% ohm
8. 1 kWh = 3.6 x 106 joule
9. Infinity
10. Junction point.

Current Electricity Very Short Answer Type Questions

Question 1.
To flow current in a conducting wire, how much charges is present in it ?
Answer:
On flowing current through the conducting wire, charges becomes zero.

Question 2.
Why Meter bridge is known by these name ?
Answer:
Because in Meter bridge, a wire of one meter length is used.

Question 3.
Two bulb are marked as 25 W and 100 W. Whose resistance will be more ?
Answer:
R ∝ \(\frac {1}{V}\), Resistance of 25 W bulb will be more.

Question 4.
What do you mean by electric power. Write its unit ?
Answer:
In any electrical circuit the rate of energy decay is called as power. Its unit is watt.

Question 5.
On which factor relaxation time depend on ?
Answer:
It depends on nature of the material of the conductor.

Question 6.
Why there is internal resistance in a cell ?
Answer:
Because, inside the cell, the motion of ions get obstacled by the collision of electrolytes molecules.

Question 7.
Why wire of Meter bridge is not made of copper wire ?
Answer:
Since the resistance of copper wire is very less and its temperature coefficient is more, therefore it is not used in Meter bridge.

Current Electricity Short Answer Type Questions

Question 1.
What is current ? Write its unit
Answer:
The electric current is defined as the rate of flow of charge through any section of a
Electric current = \(\frac {Total charge flowing}{ Time taken }\)
l = \(\frac {q}{ t}\) The SI unit of electric current is ampere (A).

Question 2.
Is electric current a scalar or a vector quantity ? Give reason.
Answer:
Electric current is a scalar quantity. This is because laws of ordinary algebra are used to add electric current and laws of vector addition are not applied for the addition of electric current.

Question 3.
Define current density. Is it scalar or vector ? Write its unit.
Answer:
Current density at a point in a conductor is defined as the amount of current flowing per unit area of the conductor held perpendicular to the flow of current.
Current density J = \(\frac {Current (l)}{ Area (S)}\) (or) \(\frac {l}{ S}\)
Current density is a vector quantity. The SI unit of current density is ampere / meter².

Question 4.
What is drift velocity ? What is its value ?
Answer:
Drift velocity is defined as the average velocity with which the velocity free electrons with which they get drifted towards the positive terminal of the conductor under the influence of the external electric field. Its value is 10^-5ms^-1

Question 5.
Is Ohm’s law applicable to all conductors ? Write conditions for its application
Or
Write the condition or under which Ohm’s law is not obeyed.
Answer:
No, Ohm’s law is not applicable for non – ohmic conductors, e.g., semiconductor diode, discharge tube, etc. It is valid only when there is no change in physical conditions of conductor i.e., temperature, length or mechanical strain etc.

Question 6.
Define specific resistance or resistivity. Write its unit and dimensional formula.
Answer:
Specific resistance or resistivity is numerically equal to the resistance offered by a conductor of unit length and unit cross-sectional area. Its unit is ohm – meter. It depends upon temperature. a’ ‘ The dimensional formula of specific resistance is [ML³T³A^-2].

Question 7.
If you are given two wires of same material, having same length but different diameters, then which wire will have higher resistance and which will have high specific resistance ?
Answer:
The thin wire (having less diameter) will have higher resistance than that of thicker one as R ∝ \(\frac { 1 }{ A }\) Both wires will have same specific resistance as they are made of same material and specific resistance is characteristic of the material of wire.

Question 8.
It is easier to start motor car during summer rather than in winter. Why ?
Answer:
The internal resistance of the battery during summer is less as compared to winter, therefore more current can be drawn from the battery.

Question 9.
When a high power heater is connected to mains, bulbs become dim. Why ?
Answer:
All electrical appliances are connected in parallel at home, therefore when power heater is used, very high current passes through it. So, potential difference falls on wires connected through mains (V = E – lr), which results in decreasing intensity of bulbs used in circuit.

Question 10.
What do you measure by meter bridge ? When is its sensitivity maximum ?
Answer:
Resistances are measured by meter bridge. Sensitivity of meter bridge is maximum when the null point is obtained at the center of wire. Moreover, all the resistances must be of same order.

Question 11.
What is the wire of meter bridge made up of ?
Answer:
The wire of meter bridge is made of manganin or constantan because it has low temperature coefficient of resistance and high specific resistance.

Question 12.
How can the sensitivity of potentiometer be increased ?
Answer:
The sensitivity of the potentiometer will be more if the potential gradient is less. For this, V should be less but more than the emf of E. The length of potentiometer should be large.

Question 13.
Write two possible reasons for obtaining deflection on one side in the experiment of potentiometer.
Answer:
The two possible reasons are as follows:

• If the emf of secondary cell in primary circuit is less than the emf of primary cell in the secondary circuit.
• If positive terminals of all the cells are not connected to the same point.

Question 14.
What do you understand by potential gradient of a potentiometer ? Give its unit
Answer:

• Fall in potential per unit length is called potential gradient. If the length of wire be / and potential difference across the wire is v, then
• Potential gradient, K =\(\frac {V}{l}\) Its unit is volt / m.

Question 15.
The potential gradient of potentiometer wire is doubled, what will happen to its null point ?
Answer:
Let emf of cell E is balanced at the length of –
E = Kl = l = \(\frac {E}{ K}\) = l ∝ \(\frac {1}{ K}\)
Hence, the null point will be at the half of the length.

Question 16.
Why the length of wire in potentiometer is more ?
Answer:
For greater sensitivity, the length of null point should be greater, for which the potential gradient should be smaller.
Potential gradient, K =\(\frac {V}{ l}\) To decrease K the value of l should be greater and F should be smaller. But, the value of V can be decreased up to a certain limit, hence the length is increased sufficiently.

Question 17.
Prove that potentiometer is an ideal voltmeter.
Answer:
When the potential difference between two points is measured by the voltmeter, then same current passes through the voltmeter, hence it measures little less than actual potential difference. But, when potentiometer measures the potential difference between two points, no current flows through it. Hence, it measures the accurate potential difference.

Question 18.
A carbon resistance has bands blue, red and green respectively. What is its resistance ?
Answer:

.’. The value of carbon resistance is 62 x 105 ohm with tolerance ± 20% .

Question 19.
A carbon resistance has bands blue, green and red respectively. Write its resistance.
Answer:

The value of carbon resistance is 65 x 102 ohm with tolerance ± 20% .

Question 20.
A carbon resistance has bands red, blue and green. What is its resistance ?
Answer:

The value of carbon resistance is 26 x 105 ohm with tolerance ±20% .

Question 21.
In high tension battery internal resistance should be high. Why ?
Answer:
If high tension battery is used in a circuit having low external resistance, current may go beyond its safety limit. If internal resistance of the battery is high, then current cannot go beyond its safety limit. So, internal resistance of high tension battery must be high.

Question 22.
What is cause of end error in a meter bridge ?
Answer:
The end error in meter bridge is due to following reasons:
The zero mark of the scale provided along the wire may not start from the position where the bridge wire leaves the copper strip and 100 cm mark of the scale may not end at the position where the wire touches the copper strip. The resistance of the copper wire and metal strip of meter bridge has not been taken in account.

Question 23.
What is Ohm’s law ? On what factors does the resistance of a conductor depend upon ?
Answer:
If all the physical conditions of any conductor as length, temperature, etc. remain constant, then the current which flows through it is proportional to the potential difference applied across the ends of the conductor. If I is the current in conductor and V is the potential difference, then
V ∝ l = V=RI
Where, R is a constant, called resistance of conductor.
For factors affecting resistance of conductor:

• Length: The resistance of conductor is directly proportional to the length of the conductor i.e., R ∝ l
• Area of cross – section: The resistance of a conductor is inversely proportional to the area of cross – section of the conductor i.e., R ∝ \(\frac{l}{A}\)
• Temperature: Increase in temperature, increases the resistance.

Combining above two laws, we get,
R ∝ \(\frac{l}{A}\)
R = p \(\frac{l}{A}\)
Where, p= a constant, called specific resistance of the material of the conductor.
Specific resistance:
We have,
R = p \(\frac{l}{A}\)
Let l = 1 And A = l, then
R = P

Thus, the specific resistance of a material is defined by the resistance of unit length and unit area of cross-section of that material.
Unit: Now, p = \(\frac{R.A}{l}\)
= \(\frac{Unit of R x Unit of A}{Unit of l}\)
= \(\frac{\mathrm{ohm} \times \mathrm{m}^{2}}{\mathrm{m}}\) = Ohm x m = Ω x m

Question 24.
What are the possible errors of a meter bridge and how can they be removed ?
Answer:
The possible errors and their removal methods are:
1. It might happen that the wire is not uniform. To remove this error, balance point should be obtained at the-middle.

2. During’the experiment, it is assumed that the resistance of L shaped plates are negligible, but actually it is not so. The error created due to this is called end error. To remove this error, the resistance box and the unknown resistance must be interchanged and then the mean reading should be taken.

3. If the jockey is pressed for a long period of time, then it gets heated and its resistance changes. Hence, jockey must not be pressed for a long interval.

Question 25.
Prove Ohm’s law on the basis of free electron theory.
or
Determine the formula for specific resistance in terms of free electron density and relaxation time.
Answer:
Consider a conductor of length l, area of cross-section A having ‘n’ No. of free electron per unit volume. If potential difference V is applied between its opposite ends then,
\(\frac { V }{ l }\)
Force experienced by each free electron will be
F = eE or F = \(\frac { eV }{ l }\)
The acceleration produced on the electron of mass m is
a = \(\frac { F }{ m}\) = \(\frac { eV }{ ml }\)
If the time interval between two successive collisions (relaxation time) is r then drift velocity is
V_d = \(\frac {eEτ }{ m }\)
= \(\frac {eVτ }{ ml }\)
But cuurent l = neAv_d
l = neA\(\left(\frac{e V \tau}{m l}\right)=\frac{n e^{2} \tau}{m} \frac{A}{l}V\)
\(\frac { V }{ l }\) = \(\frac{m}{n e^{2} \tau} \cdot \frac{l}{A}\)
If temperature remains constant, then all terms on R.H.S. will be constant, so
\(\frac { V }{ l }\) = R
This is Ohm’s law. Where R is constant called resistance.
R = \(\frac{m}{n e^{2} \tau} \cdot \frac{l}{A}\) ……….(1)
But resistance is directly proportional to length / and inversely proportional to area of cross-section A of conductor
R ∝ \(\frac { l }{A }\)
R = p\(\frac { l }{A }\) ………..(2)
From eqns. (1) and (2),
p = \(\frac{m}{n e^{2} \tau}\)

Question 26.
Obtain a relationship between current and drift velocity.
Answer:
Consider a conductor of length /and area of cross-section A. Let n be the number of electrons per unit volume.
Volume of conductor = Al
Total number of electrons = nAl.
Total charge of conductor, Q = nAle.
The conductor is now joined to a cell of potential difference V.
So, the electrons get drifted towards the positive terminal of the cell. Let the drift velocity be v_d.
Time taken to cover length l is –

t = \(\frac{l}{v_{d}}\)
l = \(\frac { Q }{t }\)
= \(\frac { nAel }{t }\)
l = nAev_d,
( v_d = \(\frac { distance}{time }\) = \(\frac { l }{t }\)
This is the required relationship.

Question 27.
Write four differences between electromotive force and potential difference.
Or
Define e.m.f. of a cell and potential difference. Give differences between them.
Answer:
e.m.f.: Work done in flowing 1 coulomb charge through a circuit is called e.m.f. of a cell When the terminals are not connected to an external circuit, the maximum potential difference between the terminals is equal to the e.m.f. of the cell. Unit of e.m.f is volt.

Potential difference:
The difference of potentials of any two points of the circuit is called potential difference.
Or
Work done in bringing unit positive charge from one point to another is called potential difference between these two points.

Differences between e.m.f. and potential difference:
e.m.f.:

• The maximum potential difference bet-ween the terminals of a cell is called its e.m.f., when the cell is in open circuit.
• This term is used for the electric sources as generator, cell, battery, dynamo, etc.
• It is established even the circuit is off.
• e.m.f. does not depend upon the resistance of the circuit.

Potential difference:

• Difference of potential of any two points of the circuit is called potential difference.
• This term is used for any two points of the circuit.
• It is established till the current is flowing through the circuit.
• It depends upon the resistance of the circuit

Question 28.
What do you understand by internal resistance of a cell ? On what factors does It depend and how ?
Or
What do you mean by internal resistance of a cell ? Write the factors affecting it.
Answer:
The resistance offered by the electrolyte of the cell during the flow of current inside the cell is called its internal resistance.
The following factors affect the internal resistance:

• Distance between the electrodes:
  As the distance increases, the internal resistance increases.
• Area of the immersed electrodes:
  As the area increases, the internal resistance decreases.
• Concentration of the electrolyte:
  As the concentration is more, the internal resistance is more.
• Temperature:
  The increase of temperature, decreases the internal resistance.

Question 29.
Establish the relationship between internal resistance of a cell, e.m.f. and extecoafresistance.
Or
Establish the relationship between the electromotive force, potential difference and internal resistance of a cell.
Answer:

Let e.m.f. of a cell be E and its internal resistance is r. If current / is flowing through a resistance R, then by Ohm’s law,
l = \(\frac { V}{R }\) ……………(1)
Where, V is the potential difference across the resistance. Now, total e.m.f. of the circuit = E and total resistance of the circuit = R + r
l = \(\frac {E}{R+r }\)
By eqns. (1) and (2), we get
\(\frac {V}{R}\) = \(\frac {E}{R+r }\)
VR + Vr = ER
Vr = ER – VR
r = \(\frac {R(E – V)}{V}\)
r = R(\(\frac {E}{V}\) – 1)
This is the required relationship.

Question 30.
Explain Kirchhoff’s laws of distribution of current through the different conduct^£
Or
Write down the Kirchhoff’s laws relating to the distribution of electric current.
Or
State and explain Kirchhoff’s laws.
Answer:
Kirchhoff’s laws:
(i) The algebraic sum of current meeting at any junction in a circuit is zero. In this law, the currents flowing towards the junction are considered as positive and those flowing  way from the junction as negative. As shown in the figure, we have

i₁ – i₂ – i₃ – i₄ – i₅ = 0
i₁ + i₄ = i₂ + i₃ + i₅

(ii) in any closed mesh (or loop) of an electrical circuit, the algebraic sum of the product of the currents and resistances is equal to the total e.m.f. of the mesh. If we go along the direction of conventional current, the potential difference will be taken as negative and opposite to it will be positive. Inside the cell, if we move from low to high potential, along the direction of conventional current, the e.m.f. will be positive.

For loop 1,
E₂ – i₂R₂ – (i₁ + i₂ )R₃ = 0
or E₂ = i₂R₂ + (i₁ + i₂ )R<sub>3

For loop 2,
i2R2 – E2 – i1R1 + E1 = 0
or E1 – E2 = i1R1 – i2R2</sub>

Question 31.
Derive the principle of Wheatstone bridge by Kirchhoffs law.
Or
Explain the principle of Wheatstone bridge and obtain the expression for balance condition by Kirchhoff s laws.
Answer:
Principle of Wheatstone bridge:
Four resistances P, Q, R and S are connected to form a quadrilateral ABCD. A cell E is connected across the diagonal AC and a galvanometer across BD. When the current is flown through the circuit and galvanometer does not give any deflection, then the bridge is said to be balanced. In this condition,
\(\frac { p }{ Q }\) = \(\frac { R }{ S }\)
This is the principle of Wheatstone bridge.

Formula derivation:
Let the current i is divided into two parts and i2, flowing through P, Q and R, S respectively. In the position of equilibrium, the galvanometer shows zero deflection, i.e,, the potential of B and D will be equal. In the closed mesh ABDA, by Kirchhoffs second law, we get

i₁P – i₂R = 0
or i₁ P = i₂R ……….(1)
Similarly, in the closed mesh BCDB, we have
i₁Q – i₂S = 0
or i₁Q = i₂S ……….(2)
Dividing eqn. (1) by eqn. (2), we get
\(\frac{i_{1} P}{i_{1} Q}=\frac{i_{2} R}{i_{2} S}\)
\(\frac{P}{Q}\) = \(\frac{R}{S}\)
This is Wheatstone bridge principle or principle of balance.

Question 32.
Explain the principle of potentiometer.
Answer:
Let AB be the wire of potentiometer of length L. A storage cell C, a key K and a rheostat Rh are connected in series with the resistance wire.
When the key is inserted, the current starts flowing through the circuit and a potential difference is established between A and B, let it is V.
∴ Potential gradient, P = \(\frac{V}{L}\)

Now, the +ve terminal of the experimental cell is connected to A and -ve to galvanometer which is connected to jockey J. When jockey is touched near A, we get the deflection in one side and if it is touched near B, the deflection is in other side. Thus, a point on AB is found such that galvanometer gives no deflection. Hence, no current flows through the galvanometer and get the null point J.

In this balanced position,
e.m.f. of the cell = Potential difference between A and J
If the length of AJ = l.
∴ E = pl
Thus, knowing p and E can be calculated.
This is the principle of potentiometer.

Question 33.
On what factors the resistance of a wire or conductor depends ? Define specific resistance and write its unit.
Or
On what factors the resistance of a conductor depends and how ?
Answer:
The factors affecting the resistance are:

• Length: The resistance of conductor is directly proportional to the length of the conductor i.e., R ∝ l
• Area of cross – section: The resistance of a conductor is inversely proportional to the area of cross – section of the conductor i.e., R ∝ \(\frac{l}{A}\)
• Temperature: Increase in temperature, increases the resistance.

Combining above two laws, we get,
R ∝ \(\frac{l}{A}\)
R = p \(\frac{l}{A}\)
Where, p= a constant, called specific resistance of the material of the conductor.
Specific resistance:
We have,
R = p \(\frac{l}{A}\)
Let l = 1 And A = l, then
R = P

Thus, the specific resistance of a material is defined by the resistance of unit length and unit area of cross-section of that material.
Unit: Now, p = \(\frac{R.A}{l}\)
= \(\frac{Unit of R x Unit of A}{Unit of l}\)
= \(\frac{\mathrm{ohm} \times \mathrm{m}^{2}}{\mathrm{m}}\) = Ohm x m = Ω x m

Question 34.
What do you understand by specific resistance or resistivity of a conductor ? Give its unit and dimensional formula.
Answer:
For specific resistance of a conductor: Refer Short Answer: Type Q. No. 33(iii). Dimensional formula of specific resistance is determined as:
As p = \(\frac{RA}{l}\)
[p] = \(\frac{[R][A]}{[l]}\)
[R] = \(\frac{[V]}{[l]}\) = \(\frac{W/P}{[l]}\) = \(\frac{\left[\mathrm{ML}^{2} \mathrm{T}^{-2}\right] /[\mathrm{AT}]}{[\mathrm{A}]}\)
= \(\frac{\left[\mathrm{ML}^{2} \mathrm{T}^{-3} \mathrm{A}^{-1}\right]}{[\mathrm{A}]}\) = [ML²T^-3A^-2
[p] = \(\frac{\left[\mathrm{ML}^{2} \mathrm{T}^{-3} \mathrm{A}^{-2}\right]\left[\mathrm{L}^{2}\right]}{[\mathrm{L}]}\)
= \(\left[\mathrm{ML}^{3} \mathrm{T}^{-3} \mathrm{A}^{-2}\right]\)

Question 35.
Give differences between specific resistance and resistance.
Answer:
Differences between specific resistance (resistivity) and resistance:

Specific resistance:

• It is defined by the resistance offered by the conductor of unit length and unit area of cross – ection.
• Its unit is ohm x m.
• It does not depend upon the length and area of cross – ection.

Resistance:

• The hindrance offered by a conductor to the flow of current is called electrical resistance.
• Its unit is ohm.
• It depends upon the length and area of cross-section of the conductor.

Question 36.
Evaluate It and I₂ as shown in the figure.

Solution:
Equivalent figure of fig. (a) is fig. (b)
In closed current BEFC, by Kirchhoff s second law,
2l₁ – 6I₂ = 0
or I₁ = 3I₂ …….(1)
In closed path ABCD
2I₁ + l(l₁ + l₂) = 10
3I₁ + I₂ = 10 …….(2)

From eqns. (1) and (2),
3 x 3I₂ + I₂ = 10
or 9I₂ + I₂ = 10
or I₂ = 1 amp.
Putting the value of 12 in eqn. (1) we get,
I₁ = 3 x l = 3 amp

Question 37.
Three resistors R₁ R₂ and R₃ are connected in series. Obtain the expression for the equivalent resistance.
Answer:
The series combination of three resistors having resistances R₁ R₂ and R₃ are shown in figure.

When this combination is connected to a cell (C) of e.m.f. E volt, then I current flows through combination.
Let the potential difference across R₁ R₂ and R₃ be V₁, V₂ and V₃ respectively. Then, by Ohm’s law,
V₁= IR₁ V₂ = IR₂ and V₃ = IR₃ .
If potential difference across A and B be V, then
V = V₁ + V₂ + V₃
or V = IR₁ + IR₂ + IR₃
V = I(R₁ + R₂ + R₃) ……(1)
If equivalent resistance of this combination be R, then
V = IR …..(2)
From eqns. (1) and (2), we get
1R = I(R₁ + R₂ + R₃)
or R = R₁ + R₂ + R₃ …(3)
Thus, when a number of resistances are connected in series with each other, the equivalent resistance of the combination is equal to the sum of their individual resistances.

Question 38.
Find out equivalent resistance of the three resistances R₁ ,R₂ and R₃ connected in parallel combination.
Answer:
The resistances R₁ ,R₂ and R₃ are connected in parallel as shown in adjacent figure. As all the resistances are connected between two points A and B, hence the potential difference between two points will be same for all. Let it be V. Let I be the total current. This current is divided into three parts at point A. If through R₁, R₂ and R₃; currents I₁ I₂ and I₃ are respectively flowing. Then,

I = I₁ + I₂ + I₃
By Ohm’s law,
I₁ = \(\frac{V}{R_{1}}\), I₂ = \(\frac{V}{R_{2}}\), I₃ = \(\frac{V}{R_{3}}\)
I = \(\frac{V}{R_{1}}\) + \(\frac{V}{R_{2}}\) + \(\frac{V}{R_{3}}\) ……….(1)
If the equivalent resistance of this combination be R, then
I = \(\frac{V}{R}\) ……….(2)
From eqns. (1) and (2), we have
\(\frac{V}{R}\) = \(\frac{V}{R_{1}}\) + \(\frac{V}{R_{2}}\) + \(\frac{V}{R_{3}}\)
\(\frac{1}{R}\) = \(\frac{1}{R_{1}}\) + \(\frac{1}{R_{2}}\) + \(\frac{1}{R_{3}}\) …………(3)
Thus, if a number of resistances are connected in parallel, the reciprocal of equivalent resistance of the combination is equal to the sum of the reciprocals of their individual resistances.

Current Electricity Long Answer Type Questions

Question 1.
Describe an experiment to compare the e.m.f. of two cells by potentiometer onTne following points :

1. Circuit diagram
2. Derivation of formula
3. Two precautions.

Or
Describe an experiment to compare the e.m.f. of two cells using a potentiometer under the following heads :

1. Labelled diagram of electric circuit
2. Formula used
3. Observation table
4. Two main precautions.

Answer:
1. Circuit diagram:
AB → Potentiometer wire
B₁ → Lead accumulator
K₁ → Plug key
Rh → Rheostat
E₁ E₂ → Experimental cells
K₂ → Two ways key
G → Galvanometer
J → Jockey.

2. Derivation of formula:
Let the first cell is having e.m.f. E, and the balancing point is obtained at distance l₁. Then by the principle of potentiometer,
E₁ = pl₁ ……(1)
Where, p is potential gradient.
Let E₂ is the e.m.f. of second cell whose balancing point is at l₂, then
E₂ = pl₂ ……(2)
Dividing eqn. (1) by eqn. (2), we get,
\(\frac{E_{1}}{E_{2}}=\frac{pl_{1}}{pl_{2}}=\frac{l_{1}}{l_{2}}\)

3. Observation tab:

4. Precautions:
The e.m.f. of lead accumulator should be greater than that of experimental cells. All the positive terminals should be connected to one point

Question 2.
Determine the internal resistance of a cell by potentiometer on the following points:

1. Labelled circuit diagram
2. Derivation of formula
3. Precautions.

Or
Determine an experiment to find out the internal resistance of a cell by potentiometer under the following points :

1. Labelled circuit diagram
2. Formula derivation
3. Observation table
4. Precautions (any two).

Answer:
1. Circuit diagram:
AB → Potentiometer wire
C → Storage cell
K → Plug key
Rh → Rheostat
E → Experimental cell
R.B. → Resistance box
G → Galvanometer
J → Jockey.

2. Formula derivation:
Let the e.m.f. of the cell is E and its internal resistance is r. When it is connected to external resistance R, its potential difference is V, then

r = R (\(\frac{E}{V}\) – 1) ……..(1)
When R is not connected, then let the balance point is found at a distance l₁ from A.
∴ E = pl₁
Similarly, when R is also connected, then let the balanced point is obtained at a distance l₂ from A.
∴ V = pl₂
Now, putting these values in eqn. (1), we get
r = R \(\left(\frac{\rho l_{1}}{\rho l_{2}}-1\right)\) = R \(\left(\frac{l_{1}}{l_{2}}-1\right)\)
This is the required formula

3. Observation table :

4. Precautions:

• The e.m.f. of the storage cell (C) must be greater than that of experimental cell (£).
• All the positive terminals must be connected to a single point

Question 3.
How are the cells connected in mixed combination ? Derive an expression for current flowing through external resistance.
Or
Prove that the current in the external circuit for a mixed combination of cells is maximum, when the internal resistance of the combination equals the external resistance.
Answer:
In this combination, series connections of equal number of cells are connected in parallel and finally providing one +ve and one -ve terminal as shown in Fig. (a). These two terminals are connected to the ends of an external resistance R so that current starts flowing through the resistance.

Suppose n cells are connected in series combination and let m be the number of such series connected in parallel. Let the e.m.f. of each cell be E and internal resistance be r. Total e.m.f. of each series combination i.e, for a row, will be nE and total internal resistance will be nr. Hence, the equivalent becomes as given in Fig. (b).

As all the cells are now in parallel, so total e.m.f. of the combination will also be nE and total internal resistance will be r’. This is shown in Fig. (c). As each resistor is of value nr and nr such resistors are connected in parallel, hence total internal resistance r’ will be calculated as:

\(\frac{1}{r’}\) = \(\frac{1}{nr}\) + \(\frac{1}{nr}\) + ………. + m terms = \(\frac{m}{nr}\) or r’ = \(\frac{nr}{m}\)
As R is the external resistance, then r’ and R are in series. Hence, total resistance of combination becomes,
R_total = R + r’ = R + \(\frac{nr}{m}\)
The current through the circuit will be given by Ohm’s law as

l = \(\frac{Total e.m.f.of battery }{Total resistance of circuit}\)

l = \(\frac{n \mathrm{E}}{\mathrm{R}+\frac{n r}{m}}\) = \(\frac{m n \mathrm{E}}{m \mathrm{R}+n r}\) ……….(1)

This is the expression for the current. For the current to be maximum, mR+nr must be minimum

mR + nr = \((\sqrt{m \mathrm{R}})^{2}+(\sqrt{n r})^{2}-2 \sqrt{m \mathrm{R}} \sqrt{n r}+2 \sqrt{m \mathrm{R}} \sqrt{n r}\) (as subtracting and adding \(2 \sqrt{m \mathrm{R}} \sqrt{n r}\))

= \((\sqrt{m \mathrm{R}}-\sqrt{n r})^{2}+2 \sqrt{m \mathrm{R}} \times \sqrt{n r}\)

But \((\sqrt{m \mathrm{R}}-\sqrt{n r})^{2}\) cannot be negative, as it is a perfect square.

mR + nr will be minimum, only when \((\sqrt{m \mathrm{R}}-\sqrt{n r})^{2}\) = 0

or \(\sqrt{m \mathrm{R}}-\sqrt{n r}\) = 0

\(\sqrt{m \mathrm{R}}\) = \(\sqrt{n r}\) ⇒ mr = nr ………(2)
∴ R = \(\frac{n r}{m}\) ………..(3)

Hence, the external resistance should be equal to the internal resistance of the battery. Under this condition the current supplied by the battery to the resistance R is maximum. The value of maximum current can be obtained by putting eqn. (2) in eqn. (1).

∴ I_max = \(\frac{mnE}{mR + mR}\)

= \(\frac{mnE}{2mR}\) = \(\frac{nE}{2R}\)
On substituting mR = nr, we get

I_max = \(\frac{mnE}{nr + nr}\) = \(\frac{mnE}{2nr}\)

= \(\frac{mE}{2r}\) .

Question 4.
explain the experiment of determining the unknown resistance of a wire with he help of meter bridge on the following points:

1. Electrical circuit
2. Principle.

Or
Describe an experiment to determine the unknown resistance by meter bridge on following points :

1. Circuit diagram
2. Description of apparatus
3. Observation table
4. Precautions.

Or
What are the possible errors in performing the experiment with metre bridge and how they can be removed ?
Answer:
1. Circuit diagram:

Where ,
AC→ wire
E → cell
R → resistance box
S → unknown resistance,
G → galvanometer
K → key.

2. Description of apparatus:
It consists of 1 meter long manganin or constant resistance wire, fixed on a wooden plank. Thick steel or brass strips are fixed as shown in the figure with two gaps. In one gap, resistance box R and in other, unknown resistance S are connected. A, C and D are terminals. A jockey slides on the wire.

3. Formula derivation or principle:
Meter bridge consists of 1 m long constant-an wire AC, fixed on a wooden plank. In two gaps resistance R and unknown resistance S are connected. Galvanometer G is connected between B and D, where B is sliding point i. e., jockey.
A cell E, with a plug key K is connected between A and C.
Let null point is obtained at a distance l from A.
∴ AB = l cm
and BC = (100 – l)cm
If x be the resistance per unit length, then Resistance offered by AB is P = lx
and resistance offered by BC is Q = (100 – l)x
Now, by the principle of Wheatstone bridge,

\(\frac{P}{Q}\) = \(\frac{R}{S}\)

S = \(\frac{R(100 – l)}{l}\)
Wheatstone bridge is sensitive when all the four resistances are of same order. Hence, metre bridge is also suitable for the resistance of same order.

4. Observation table:

5. Precautions:

• The connection should be tight.
• The plugs of R.B. should not be loose.
• The current should be passed only when readings are to be taken.
• Jockey should not be rubbed with the wire.

Possible errors and their removal:
1. It might happen that the wire is not uniform. To remove this error, balance point should be obtained at the-middle.

2. During’the experiment, it is assumed that the resistance of L shaped plates are negligible, but actually it is not so. The error created due to this is called end error. To remove this error, the resistance box and the unknown resistance must be interchanged and then the mean reading should be taken.

3. If the jockey is pressed for a long period of time, then it gets heated and its resistance changes. Hence, jockey must not be pressed for a long interval.

Question 5.
How are cells connected in series ? Derive an expression for current flowing through outer circuit. When is this combination useful ?
Answer:
In this combination, the -ve terminal of one cell is connected to the + ve terminal of second cell, whose -ve terminal is connected to the +ve terminal of third one and so on as shown in Fig. (a). Let n cells each of e.m.f. E and internal resistance r be connected in series through an external resistance R, then

Total e.m.f. of this combination = n E ’ and total internal resistance
r’ = r + r + r +…………….+ n times
= nr
The series combination of n cells is equivalent to a single cell having e.m.f. «E and internal resistance nr. This is shown in Fig. (b).
Now nr and external resistance R are in series. So, the equivalent resistance of circuit becomes R + nr Applying Ohm’s law, current flowing through the circuit is given by –
l = \(\frac{e.m.f. of battery }{Total resistance}\)
= \(\frac{nE }{nr + R}\)
This is the expression for current flowing through the external resistance R. If r « R, then nr + R * R.
Hence, from eqn. (1), we get
l = n. \(\frac{E }{R}\)
= n x Current flowing through each cell.

Utility:
Thus, if the internal resistance of each cell is negligible as compared to external resistance, the current flowing through the battery is n times the current supplied by each cell.
So, the cells should be connected in series only when the internal resistance of each cell is much less than the external resistance.

Question 6.
n cells are connected in parallel combination with internal resistance. Derive an expression for current flowing through external resistance. When is this combination useful?
Answer:
Let n cells be connected in parallel and e.m.f. of each cell be E and internal resistance be r. Since, all the positive terminals of cells connected to point A and -ve terminals connected to the point B, the total e.m.f. of battery will be E (because in parallel combination potential difference remains same).

Since the cells are connected in parallel, therefore their internal resistance will also be in parallel combination. Let the equivalent internal resistance be r’
∴ \(\frac{1 }{r’}\) = \(\frac{E }{R}\) + \(\frac{E }{R}\) + …………. + n times \(\frac{n }{r}\)
or r’ = \(\frac{r }{n}\)
Hence, the equivalent circuit becomes

Where, r’ is the total resistance of the combination of cells. As R and r’ are in series, so the total resistance of the circuit becomes
= R + r’ = R + \(\frac{r }{n}\)
Current through external resistance R will be given by Ohm’s law as
l = \(\frac{Total e.m.f.of battery }{Total resistance of circuit}\)
l = \(\frac{E}{R+\frac{r}{n}}\) = \(\frac{n E}{n R+r}\)
This is the required expression.
If R << r, then nR + r≈r
Now, from eqn. (1), we have
I = n \(\frac{E}{r}\) = n x Current given by one cell .

Utility:
Thus, if internal resistance of each cell is much greater than the external resistance, then the current flowing through the battery is n times the current through each cell i.e., maximum current is obtained. So, the cells should be connected in parallel when internal resistance of each cell is much greater than the external resistance.

Current Electricity Numerical Questions

Question 1.
The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4Ω, what is the maximum current that can be drawn from the battery? (NCERT)
Solution:
Given: E = 12 V; r – 0.4 Ω
Current l = \(\frac{E}{R+r}\)
For current to be maximum R = 0
I_max = \(\frac{E}{r}\) = \(\frac{12}{0.4}\) = 30A

Question 2.
A battery of emf 10V and internal resistance 3) is connected to a resistor. If the current in the circuit ¡s 0.5A. What is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed? (NCERT)
Solution:
Given:
E =10V; r = 3Ω l = 0.5A

l = \(\frac{E}{R + r}\)
R+r = \(\frac{E}{l}\)
R = \(\frac{E}{l}\) – r = \(\frac{10}{0.5}\) – 3 = 20 – 3 = 17Ω
Now, V = E – lr = 10 – 0.5 x 3 = 10 – 1.5 = 8.5V

Question 3.
(a) Three resistance IΩ, 2Ω and 3Ω are combined in series. What is the total resistance of the combination ?
(b) If the combination is connected to a battery of emf 12V and negligible internal resistance, obtain the potential drop across each resistor. (NCERT)
Solution:
(a) Given:
R₁ = IΩ; R₂ = 2Ω; R₃ = 3Ω
R₂ = R₂ + R₂ + R₂ = 1 + 2 + 3 = 6Ω .
(b) E = 12V; r = 0
l = \(\frac{E}{R+r}\) = \(\frac{E}{R_{S}+0} = \frac{12}{6}\)
I = 2A
Potential difference across (R₁)
V₁ = IR₁ = 2 x l = 2V
Potential difference across (R₂)
V₂ = IR₂ = 2 x 2 = 4V
Potential difference across (R₃)
V₃ = IR₃ = 2 X 3 = 6V.

Question 4.
(a)Three resistors 2Ω, 4Ω and 5Ω are combined in parallel. What is the total resistance of the combination ?
(b) If the combination is connected to a battery of emf 20V and negligible internal resistance, determine the current through each resistor and the total current drawn from the battery. (NCERT)
Solution?:
(a) Given:
R₁ = 20; R₂ = 40; R₃ = 50
Equivalent resistance:
\(\frac{1}{R_{p}}\) = \(\frac{1}{R_{1}}\) + \(\frac{1}{R_{2}}\) + \(\frac{1}{R_{3}}\)
= \(\frac{1}{2}\) + \(\frac{1}{4}\) + \(\frac{1}{5}\) = \(\frac{10+5+4}{20}\) = \(\frac{19}{20}\)
∴ \(\frac{1}{R_{p}}\) = \(\frac{20}{19}\) Ω

(b) E = 20V; r = 0
Current through different resistors,
l₁ = \(\frac{E}{R_{1}}\) = \(\frac{20}{2}\) = 10A
l₂ = \(\frac{E}{R_{2}}\) = \(\frac{20}{4}\) = 5A
l₃ = \(\frac{E}{R_{3}}\) = \(\frac{20}{5}\) = 4A
Total current drawn
l = l₁ + l₂ + l₃ = 10 + 5 + 4 = 19A

Question 5.
At room temperature (27°C) the resistance of a heating element is 100Ω. What is the temperature of the element if the resistance is found to be 117 Ω, given that temperature coefficient of the resistor material is 1.70 x 10^-4 °C^-1 ? (NCERT)
Solution:
Given:
t₁ = 27 °C
R₁ = 1000
R₂ = 1170
α = 1.70 x 10^-4 °C^-1
We know that, α = \(\frac{R_{2}-R_{1}}{R_{1}\left(t_{2}-t_{1}\right)}\)
t₂ – t₁ = \(\frac{R_{2}-R_{1}}{R_{1} \alpha}\)
= \(\frac{117-100}{170 \times 10^{-4} \times 100}\)
t₂ – t₁ = 1000
t₂ = 1000 + t₁ = 1000 + 27 = 1027 °C

Question 6.
A negligible small current is passing through a wire of length 15 m and uniform cross – section 6.0 x 10^-7 m² and its resistance is measured to be 5.0ΩWhat is the resistivity of the material at the temperature of the experiment ? (NCERT)
Sol. Given:
l = 15m; A = 6.0 x l0^-7m²; R = 5.0Ω
using R = \(\frac { pl }{ A }\)
p = \(\frac {RA}{ l }\) = \(\frac{5 \times 6 \times 10^{-7}}{15}\) = 2.0 x l0^-7Ωm

Question 7.
Determine the current in each branch of the network shown in figure. (NCERT)

solution:
\(\frac {P}{ Q }\) = \(\frac {10}{5}\) = \(\frac {2}{ 1 }\) and \(\frac {R}{S }\) = \(\frac {5}{ 10 }\) = \(\frac {1}{ 2 }\).
i.e \(\frac {P}{ Q}\) = \(\frac {R}{ S}\)

Therefore, bridge is not in equilibrium. Current flowing through different branches is as shown in fig. Now applying Kirchhoffs loop rule.

For loop ABDA
10I₁ + 5I₂ – 5(I – I₁) = 0
3I₁ + l₂ – I = 0 ……(1)

For loop BCDB.
5(I₁ – I₂) – 10 (I – l₁ + I₂) – 5I₂ = 0
or I₁ – I₂ – 2 (I – I₁ + I₂) I₁ = O
or 3I₂ – 4I₂ – 2I = 0 …..(2)
By eqns. (1) and (2), 5I₂ + I = 0
I = – 5I₂
I₂ = – \(\frac {1}{ 5 }\) I …….(3)
And I₁ = \(\frac {2}{ 5 }\) I …….(4)

For loop ADCA,
5(I – I₁) + 10 (1 – l₁ + l₂) + 10I = 10
5I – 3I + 2I₁ = 2

Question 8.
Find out effective resistance between points A and B for circuit given below:

Solution:
\(\frac {1}{ R}\) = \(\frac {1}{ 2 + 2 + 2 }\) + \(\frac {1}{ 3 }\)

\(\frac {1}{ R}\) = \(\frac {1}{6}\) + \(\frac {1}{3}\)

\(\frac {1}{ R }\) = \(\frac {1 + 2}{ 6 }\) = \(\frac {3}{6}\)
R = \(\frac {6}{3}\) = 2Ω

Question 9.
Find out effective resistance between points A and B for circuit given below:

\(\frac{1}{\mathrm{R}_{1}}\) = \(\frac {1}{ 4}\) + \(\frac {1}{ 4}\) = \(\frac{1}{\mathrm{R}_{1}}\) = \(\frac {2}{ 4}\)

R₁ = \(\frac {4}{2}\) = 2Ω

\(\frac{1}{\mathrm{R}_{2}}\) = \(\frac {1}{ 6}\) + \(\frac {1}{ 6}\) =\(\frac{1}{\mathrm{R}_{2}}\) = \(\frac {2}{ 6}\)

R₂ = \(\frac {6}{ 2}\) = 3Ω
Effective resistance R = R₁ + R₂
R = 2 + 3 = 5Ω

Question 10.
10⁹ electrons flows from point A to B in 10^-3 second. Find out magnitude and direction of electric current.
Solution:
Formula: I = \(\frac {ne}{t}\)
Given: n = 10⁹ t = 10^-3 sec.
Putting the given value in the formula, we get
I = \( \frac{10^{9} \times 16 \times 10^{-19}}{10^{-3}}\)
or l = 1.6 x l 0^-7 ampere.
Direction of electric current will be from B to A. Ans.

Question 11.
150 m A current flows through a conductor. How many electrons will flow through it in 20 sec ?
Solution:
Given:
I = 150 mA = 0.15 A, t = 20 sec.
Formula:
n = \(\frac {It}{e}\) = \(\frac{0.15 \times 20}{1 \cdot 6 \times 10^{-19}\)

n = \(\frac{3}{1 \cdot 6} \times 10^{19}\) = 1.875 x 10¹⁹

Question 12.
200 mA current flows through a conductor. How many electrons will flow through it in 5 sec ?
Solution:
Given:
I = 200 mA = 0.2 A, t = 5 sec
Formula:
n = \(\frac {It}{e}\) = \(\frac{0\cdot 2\times 5}{1\cdot 6\times 10^{-19}}\)

n = \(\frac{1}{1 \cdot 6} \times 10^{19}\)
n = 0.625 x 10¹⁹

Question 13.
The length of a wire becomes twice when stretched. How many times resistance will increase ?
Solution:
On stretching the wire, radius of the wire will decrease but volume will remain same. Let l₁ and r₁ be initial length and radius of wire respectively. On stretching, the length becomes l₂ say and radius r₂
Initial volume = Final volume

From the formula, R = p \(\frac {1}{A}\)

Putting the value of \(\left(\frac{r_{2}}{r_{1}}\right)^{2}\) from eqn. (1) in eqn. (2), we get

As per the question, l₂ = 2l₁
\(\frac{R_{1}}{R_{2}}\) = \(\left(\frac{l_{1}}{2 l_{1}}\right)^{2}\) = \(\frac {1}{4}\)
R₂ = 4R₁
Hence, the resistance of wire is increased four times.

Question 14.
The ratio of area of cross-section of two wires made of same metal and equal length is 2 : 1. It applied potential difference between their ends are same then what will be the ratio of current among them ?
Solution:

Question 15.
The ratio of length of two wire, made of same metal and equal area of cross-section is 2 : 1. If the applied potential difference between their ends are same, then what will be the ratio of current following among them ?
Solution:

Question 16.
125 mA current flows through a lamp in 10 sec. How many electrons will flow across it ?
Solution:
Given:
I = 125 mA = 0.125 A. t = 10 sec.

MP Board Class 12th Physics Important Questions

MP Board Class 12th Biology Important Questions Chapter 16 Environmental Issues

Environmental Issues Important Questions

Environmental Issues Objective Type Questions 

Question 1.
Choose the correct answer:

Question 1.
Disease caused due to mercury pollution is:
(a) Methenamine
(b) Minimata
(c) Asbestosis
(d) Liver inflammation.
Answer:
(b) Minimata

Question 2.
Plants are natural air purifiers because they exhibit :
(a) Respiration
(b) Photosynthesis
(c) Transpiration
(d) Drying.
Answer:
(b) Photosynthesis

Question 3.
Metal found in atmosphere is :
(a) Cadmium
(b) Lead
(c) Mercury
(d) Zinc.
Answer:
(b) Lead

Question 4.
Burning of fossil fuel results in:
(a) SO₂ pollution
(b) NO₂ pollution
(c) N₂O pollution
(d) NO pollution.
Answer:
(a) SO₂ pollution

Question 5.
Increase of the concentration of which gas results greenhouse effect :
(a) CO₂
(b) CO
(c) O₂
(d) Nitrogen oxide.
Answer:
(a) CO₂

Question 6.
Gas responsible for depletion of O₃ in atmosphere is :
(a) CFC
(b) NO₂
(c) CO₂
(d) SO₂
Answer:
(a) CFC

Question 7.
Carbon monoxide is the chief pollutant of :
(a) Water
(b) Air
(c) Noise
(d) Soil.
Answer:
(b) Air

Question 8.
Effect of air pollution is seen in :
(a) Leaves
(b) Flower
(c) Forests
(d) None of these.
Answer:
(b) Flower

Question 9.
Shrinking of leaves occurs by :
(a) SO₂
(b) O₂
(C) H₂S
(d) CO.
Answer:
(a) SO₂

Question 10.
Example of greenhouse gas is :
(a) CO₂
(b) CH₄
(c) CFC
(d) All of these.
Answer:
(d) All of these.

Question 11.
Gas produced during combustion of fossil fuels is :
(a) CO₂
(b) CH₄
(c) CFC
(d) N₂O
(a) CO₂

Question 12.
Gas used in refrigeration is :
(a) Freon
(b) N₂O
(c) CH₄
(d) CO₂.
Answer:
(a) Freon

Question 13.
Radiation emitted due to heating of earth is:
(a) UV
(b) Infrared
(c) Gamma
(d) None of these.
Answer:
(b) Infrared

Question 14.
Gas responsible for depletion of atmospheric ozone layer is:
(a) CO₂
(b) CH₄
(c) CFC
(d) O₂
Answer:
(c) CFC

Question 2.
Fill in the blanks:

1. ………………….. is a chief green house gas.
2. ………………….. is the measurement unit of water pollution.
3. ………………….. and ………………….. gases are responsible for acid rain.
4. ………………….. gas is essential for life. (MP 2009 Set B)
5. The substances which produce pollution are called ………………….. (MP 2013)
6. Strong, loud, unpleasant or untolerable sound is called ………………….. (MP 2013)
7. We can ………………….. the quantity of CO₂ from forestation.
8. CO₂, CH₄, N₂O, CFCs are………………….. gases.
9. ………………….. is discharged in Bhopal gas disaster.
10. In human DDT is reached by …………………..
11. ………………….. is also known as chemical weeds.
12. Pollution is the …………………. changes which occurs in atmosphere.
13. Deficiency of soil nutrients is called …………………..
14. The percentage of CO₂ of atmosphere can be ………………….. by forestation. (MP 2009 Set D)

Answer:

1. CO₂
2. BOD
3. SO₂ and NO₂
4. O₂
5. Pollutant
6. Noise
7. Lost
8. Green house
9. Methyl isocyanate
10. Food chain
11. Ozone
12. Unwanted
13. Negative pollution
14. Reduced.

Question 3.
Match the followings:
I.

Answer:

1. (c)
2. (f)
3. (e)
4. (b)
5. (d)
6. (a)
7. (g)
8. (h)

II.

Answer:

1. (b)
2. (c)
3. (d)
4. (a)

Question 4.
Write the answer in one word/sentences:

1. Write full name of BOD.
2. What is the hearing capacity of man?
3. Name the fish used to control mosquito.
4. What is the concentration of CO₂ in environment?
5. When is World Environment Day celebrated?
6. Write the names of two main gases which pollute air.
7. Write the name of highly polluted river of India.
8. Name the term used, for the increase in atmospheric temperature, due to increase in CO₂ concentration.
9. What is the amount of oxygen taken up by microorganisms, that decompose waste matter?
10. Write full name of CFC.
11. Write the name of a chief greenhouse gas.
12. Write the name of gas responsible for ozone layer depletion.
13. Who is the greatest enemy of nature and organism? (MP 2013)
14. When we celebrated ozone day?

Answer:

1. Biological Oxygen Demand
2. 10 – 12 decibel
3. Gambussia
4. 0 03%
5. 5th June
6. SO₂and CO
7. Ganga
8. Green House effect
9. B. O. D
10. Chlorof – luorocarbon
11. CO₂
12. CFC
13. Global warming
14. 16December.

Environmental Issues Very Short Answer Type Questions

Question 1.
What is the definition of pollution?
Answer:
Pollution is defined as an undesirable changes in physical, chemical or biological characteristics of air, land, wafer and soil.

Question 2.
What are the essential components of biodiversity?
Answer:
Essential components of biodiversity are:

1. Genetic diversity.
2. Species diversity.
3. Ecological diversity.

Question 3.
When and how photochemical smog is formed?
Answer:
Photochemical smog is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves air borne particles and ground level ozone. Peroxyacetyl Nitrate (PAN) is present in the photochemical smog. It causes damage to respiratory system and environment system. (The word smog is derived from smoke and fog.)

Question 4.
Name two plants which uses carbon monoxide (CO).
Answer:
Two plants which uses CO are:

1. Daucus carota,
2. Ficus variegata.

Question 5.
Name the types of water pollution based on source of water.
Answer:
Types of water pollution based on source of water:

1. Underground water pollution
2. Surface water pollution
3. Lake water pollution and
4. River water pollution.

Question 6.
How does fertilizers pollute water?
Answer:
Excess fertilizers used in the field are drained into the pond and river, where they proliferate growth of algae, which spread all over the surface of the water and cut off oxygen supply for lower aquatic organisms. Due which lower aquatic organisms dies. This is known as eutrophication.

Question 7.
Give harmful effects of cutting of forest.
Answer:
Harmful effects of cutting of forest are:

1. It increases landscape.
2. It decreases fertility of the soil.
3. Rainfall reduces and become uncontrolled.

Environmental Issues Short Answer Type Questions

Question 1.
What is acid rain? Write any two effects of acid rain on human beings.
Answer:
Acid rain:
SO₂ gas is released into the environment by burning of fossil fuels containing sulphide from industries, example Coal. In presence of moisture, SO₂ reacts with water and forms the droplets of sulphurous and sulphuric acid in the environment. Likewise nitrogen oxides released from motor vehicles, burning materials and chemical industries also react with water to produce the droplets of nitric acid. The droplets of sulphurous, sulphuric acid and nitric acids fall down on the earth with rainwater and thus, it is known as acid rain.

• SO₂ + \(\frac { 1 }{ 2 }\) O₂ → SO₃
• H₂O + SO₃ → H₂SO₄
• H₂O + NO₂ → HNO₃

Effects on human beings : Skin diseases, irritation, metabolic diseases.

Question 2.
Write the effect of air pollution on plants.
Answer:
Effect of air pollution on plants:

1. Increase in the concentration of SO₂ causes chlorosis of leaves in plants.
2. The cells and chlorophyll of leaves are degraded and fall down.
3. Vegetative and reproductive growth is inhibited.
4. The development of plant is inhibited.

Question 3.
Write short note on pollution caused due to combustion activities.
Answer:
Combustion of fuel, such as wood, coal, natural gas for cooking and for some other puiposes gives out gases like CO₂, CO, SO₂ and consumes oxygen from the air.

Question 4.
Write preventive measures to control air pollution.
Answer:
Preventive measures to control air pollution:

1. Industrial smokes must be filtered before releasing it into the atmosphere.
2. Tree plantation should be increased and deforestation prevented.
3. Use of automobiles should be minimized which reduce the nitrogen contents in the atmosphere.
4. The use of crude fuels should be avoided and use of high quality fuels should be recommended.
5. Nuclear explosions should be avoided.
6. Legal control of air pollution.
7. Plantation of air purifying plants.
8. Development of parks and gardens in cities.

Question 5.
Write any four measures to control greenhouse effect.
Answer:
Following important measures can be sited as the base steps towards controlling greenhouse effect:

1. The aim is achieved to some extent by reducing the consumption of fossil fuels such as coal and petroleum. This can be achieved by depending more on non – conventional renewable sources of energy such as solar, wind, tidal, biogas and nuclear energies.
2. Disposing of the greenhouse gases as they are formed elsewhere than in the atmosphere.
3. By recovering greenhouse gases present already in the atmosphere and disposing them off elsewhere.
4. Prevention of deforestation and planting of more trees.

Question 6.
Write short note:

1. Bio – magnification.
2. UV rays.
3. Biodegradable pollutants.
4. Non – biodegradable.

Answer:
1. Bio – magnification:
Bio – magnification, also known as bio-amplification or biological magnification is the increasing concentration of a substance, such as a toxic chemical, in the tissues of organisms at successively higher levels in a food chain.

2. UV rays:
Sunlight is the chief source of ultraviolet rays. The rays of sunlight having a wavelength range from 200 to 390 nm are called as UV rays.

Effect of UV rays:
They have a direct effect on living cells. DNA and other chemical substances in cells are inactivated due to UV rays. Prevention of replication of the DNA molecule and its distortion cause many ill effects.

3. Biodegradable pollutants:
The pollutants which are degraded by natural factors and decomposed by natural activities are known as biodegradable pollutants, e.g., Domestic sewage, heat. The domestic sewage can be rapidly decomposed by natural processes or in engineered system (sewage treatment plant) that enhance natures great capacity to decompose and recycle.

4. Non – biodegradable:
The pollutants which cannot be purified by natural methods are called non-biodegradable pollutants. Plastic products, many chemicals, DDT, long chain detergents, glass aluminium, mercury salt and other synthetic products manufactured by man come under this category. These non – biodegradable pollutants not only accumulate but often “biologically magnified” as they move in biochemical cycles and along food chains.

Question 7.
What is the effect of SO₂ in the environment?
Answer:

Question 8.
Write only the sources of water and air pollution.
Answer:
1. Sources of water pollution : Following are the chief sources of water pollution:

(a) Human sources:

• Domestic sewage
• Industrial effluents
• Agricultural wastes
• Oil pollution
• Thermal and nuclear power station.

(b) Natural sources:
Water pollution takes place by natural ways like soil erosion, mixing of metallic substances, plant leaves, humus and faecal matter of animals etc.

2. Sources of air pollution : Following are the chief sources of air pollution:

(a) Human sources:

• Combustion activities
• Industrial activities
• Agricultural works
• Use of solvents
• Activities concerned with atomic energy.

(b) Natural sources:
Volcano and its lava, ash, dust, smoke of forest fire, winds, cyclone. Decomposition of matters in the swamp water and liberation of methane gas and different compounds of hydrogen from forests plants, various pollen grains etc.

Question 9.
Write a note on the effect of water pollution on aquatic organisms.
Answer:
Effect of water pollution on aquatic plants:

1. Inorganic nitrates and phosphates in excess amount stimulates excessive plant growth in lakes and reservoirs. These plants deplete the oxygen contents of the water during night. This leads to suffocation of fish and other aquatic life.

2. The rapid algal growth leads to the diminishing of nutrient in the medium causing rapid decay of algal filament. This increases productivity of lake and stream water brought about by nutrient enrichment is called eutrophication.

3. The number of microorganisms increases in polluted water.

4. Siltation occurs in water.

5. Temperature of water increases and O₂ ratio is reduced.

Effect of water pollution on aquatic animals : Animal life depends on aquatic plants. Aquatic animals are affected from water pollution as follows:

1. Decrease in the value of B.O.D. resulting in the number of aquatic animals.
2. Animals found in freshwater and killed.
3. Animal diversity is also decreased and fishes suffer from various types of diseases.
4. Terrestrial animals are also affected by the use of polluted water.

Question 10.
Write the measures for control and prevention of water pollution.
Answer:
Measures for control and prevention of water pollution are:

Preventive measures:

1. Use of harmful pesticides and weedicides must be stopped completely.
2. Discharge of effluents into rivers, lakes and sea should be strictly prohibited without treatment.
3. Oil spill should be prevented.
4. Proper disposal of sewage so, that it does not find its way into water bodies.
5. Preventing bathing, washing cloths, throwing dead bodies and other wastes into water source.

Curative measures:

1. Adequate waste water treatment:
The domestic sewage and the industrial waste should be properly treated before its disposal into water ways.

Waste water treatment involves three steps :

(a) Primary treatment – During this treatment large objects and suspended undissolved solids are removed and converted into the sludge, a valuable fertilizer.

(b) Secondary treatment – Aeration is supplied to promote bacterial decomposition, followed by chlorination to reduce its content of bacteria.

(c) Tertiary treatment – During this phase nitrates and phosphates are removed. The treated water is then released. Sewage treatment is quite expensive and in many developing countries only the first two steps are followed.

2. Treatment of industrial effluents:
Industrial effluents should be properly treated to remove the pollutants. These involve neutralization of acids and alkalies, removal of harmful chemicals, coagulation of colloidal impurities, precipitation of metallic compounds and reducing the temperature of wastes to decrease thermal pollution. Chemical oxidation can be achieved by chlorination through reaction with ozone. However, there are certain chemicals which are difficult to remove.

3. Recycling:
One of the best methods of prevention and control of water pollution is the recycling of the various kinds of pollutants and wastes, example Dung of cow and buffalo can be used for the production of gobar gas a cheap source of fuel and also as manure.

Question 11.
Write short notes on air pollution caused due to industries.
Answer:
Industrial pollution is caused by industrial pollutants which are released by the industries such as SO₂, CO₂, CO, H₂S and hydrocarbons together with dust and smoke. These are produced by the burning of coal and petroleum. The chemical industries releases HC₁, Cl₂, nitrogen oxide, oxides of copper, zinc, lead, arsenic etc. Industrial pollutants causes air pollution and water pollution.

Question 12.
Write the effects of noise pollution.
Answer:
Effects of Noise pollution:

1. The more acute and immediate effect of noise pollution is impairing of hearing leading to auditory fatigue and may finally lead to. deafness.
2. Interference with speech communication.
3. Noise pollution leads to neurosis, anxiety hypertension, cardiovascular disease, hepatic stress, giddiness.
4. Annoyance leading to ill – temper, bickering, mental disorientation and violent behaviour.
5. The high intensity of noise pollution can cause blood vessels to contract, skin becomes pale, muscles to contract and adrenaline to be short into blood stream with consequence rise in blood pressure. This ultimately results in tension and nervousness.
6. Affects different metabolic activities.

Question 13.
What are the various constituents of domestic sewage? Discuss the effects of sewage discharge on a river.
Answer:
Domestic sewage are the waste originating from the kitchen, toilet, laundry and other sources. They contain impurities such as suspended solid (sand, salt, clay), colloidal materials (faecal matters, bacteria, plastic and cloth fiber), dissolved materials (nitrate, phosphate, calcium, sodium, ammonia) and disease – causing microbes.

When organic wastes from the sewage enter the water bodies, they serve as a food source for microorganisms such as algae and bacteria. As a result, the population of these microorganisms in the water body increases. Here, they utilize most of the dissolved oxygen. for their metabolism. This results in an increase in the levels of BOD in river water and results in the death of aquatic organisms. Also, the nutrients in the water lead to the growth of planktonic algal, causing algal bloom. This causes deterioration of water quality and fish mortality.

Question 14.
List all the wastes that you generate at home, school or during your trips to other places, could you very easily reduce. Which would be difficult or rather impossible to reduce?
Answer:
Wastes generated at home include plastic bags, paper napkin, toiletries, kitchen wastes (such as peelings of vegetables and fruits, tea leaves), domestic sewage, glass, etc. Wastes generated at school include waste paper, plastics, vegetable and fruit peels, food wrapping, sewage, etc.

Wastes generated at trips or picnics include plastic, paper, vegetable and fruit peels, disposable cups, plates, spoons etc. Yes, wastes can be easily reduced by the judicious use of the above materials. Wastage of paper can be minimized by writing on both sides of the paper and by using recycled paper.

Plastic and glass waste can also be reduced by recycling and re-using. Also, substituting plastics bags with biodegradable jute bags can reduce wastes generated at home, school or during trips. Domestic sewage can be reduced by optimizing the use of water while bathing, cooking, and other household activities. Non – biodegradable wastes such as plastic, metal, broken glass, etc. are difficult to decompose because microorganisms do not have the ability to decompose them.

Question 15.
Write preventive measures of sound pollution.
Answer:
Preventive measures of noise pollution:

1. Noise pollution can be controlled by designing quieter machines, proper lubrication and better maintenance of machines. Noise producing parts of machines may be covered by suitable insulating materials.
2. Noise producing industries should be installed away from residential areas.
3. Use of public addressing systems should be restricted at a fixed intensity and hours of the day.
4. Stuffing of cotton plugs in the ear or use of earmuffs and minimise the danger of occupational exposure of noise.
5. Trees absorb sound vibrations and thus, reduce the noise pollution. Thus, plantation of trees along highways, establishment of parks help in reducing noise pollution.
6. By use of silencer in all automobiles and engines.

Question 16.
How many types of pollution are there? Explain in brief.
Answer:
Pollution are of following five types:

1. Air pollution
2. Noise pollution
3. Water pollution
4. Radioactive pollution
5. Soil pollution.

1. Air pollution – Pyrotechnics results in the release of harmful gases like CO₂, CO and SO₂ in the environment which produces various types of diseases in living beings.

2. Noise pollution – Pyrotechnics produces the unwanted sound dumped into the atmosphere leading to health hazards.

3. Water pollution – Pyrotechnics produces some waste materials, on reaching water it causes water pollution.

4. Radioactive pollution – Pollution created due to radioactive substance is called radioactive pollution. Atomic energy centres and bombarding also causes radioactive pollution.

5. Soil pollution – Any change in physical and chemical characteristics of soil due to addition of unwanted substances which adversely affects productivity of soil is termed as soil pollution.

Question 17.
Discuss the role of women and communities in protection and conservation of forests.
Answer:
Women and Communities have played a major role in environmental conservation movements. The Bishnoi community in Rajasthan strictly believes in the concept of living peacefully with nature. In 1731, the King of Jodhpur ordered his ministers to arrange wood for the construction of his new palace. For this purpose, the minister and the workers went to bishnoi village. There, a Bishnoi woman called Amrita Devi along with her daughter and hundreds of other Bishnoi’s showed the courage to step forward and stop them from cutting trees.

They embraced the trees and lost their lives at the hands of soldiers of the king. This resistance by the people of the village forced the king to give up the idea of cutting trees. The Chipko movement was started in 1974, in the Garhwal region of the Himalayas. In this movement, the women from the village stopped the contractors from cutting forest trees by embracing them.

Question 18.
What measures, as an individual you would take to reduce environmental pollution?
Answer:
The following initiatives can be taken to prevent environmental pollution:

Measures for preventing air pollution:

• Planting more trees.
• Use of clean and renewable energy sources such as CNG and Bio – fuels.
• Reducing the use of fossil fuels.
• Use of catalytic converters in automobiles.

Measures for preventing water pollution:

• Optimizing the use of water.
• Using kitchen waste water in gardening and other household purposes measures for controlling noise pollution :
  Avoid burning crackers on Diwali , Plantation of more trees.

Measures for decreasing solid waste generation:

• Segregation of waste.
• Recycling and reuse of plastic and paper.
• Composting of biodegrable kitchen waste.
• Reducing the use of plastics.

Question 19.
What are the causes of air pollution?
Answer:
The causes of air pollution:
The main causes of air pollutions are fossil fuels industries, factories and particulate matter are produced due to combustion of petrol, diesel, kerosene etc. in vehicles, houses and factories which pollute air. In thermal power plants, steel and glass industries, paper and sugar mills etc. combustion of coal and furnace oil produce carbon monoxide, carbon dioxide, sulphur dioxide, ash, dust particles and some heavy metals which are released into atmosphere. Similarly various types of chemicals released from cloth mills, cement industries, asbesters industries, pesticides industries etc. also causes air pollution.

Environmental Issues Long Answer Type Questions

Question 1.
Discuss the causes and effects of global warming. What measures need to be taken to control global warming?
Answer:
Global warming:
Global warming is defined as an increase in the average temperature of the Earth’s surface due to greenhouse effect.

Causes of global warming:
Global warming occurs as a result of the increased concentration of greenhouse gases in the atmosphere. Greenhouse gases include carbon dioxide, methane and water vapour. These gases trap solar radiation released back by the earth. Global warming is a result of industrialization, burning of fossil fuels, and deforestation.

Effects of global warming:
Global warming is defined as an increase in the average temperature of the Earth’s surface. It has been observed that in the past three decades, the average temperature of the Earth has increased by 0-6°C. As a result, the natural water cycle has been disturbed resulting in changes in the pattern of rainfall. It also changes the amount of rainwater. Also, it results in the melting of polar ice caps and mountain glaciers, which has caused a rise in the sea level, leading to the inundation of coastal regions.

Control measures for preventing global wanning:

• Reducing the use of fossil fuels.
• Use of bio – fuels.
• Improving energy efficiency.
• Use of renewable source of energy such as CNG, etc.
• Reforestation.
• Recycling of materials.

Question 2.
Write critical notes on the following:

1. Eutrophication,
2. Biological magnification,
3. Groundwater depletion and ways for its replenishment.

Answer:
1. Eutrophication:
It is the natural ageing process of lake caused due to nutrient enrichment. It is brought down by the runoff of nutrients such as animal wastes, fertilizers, and sewage from land which leads to an increased fertility of the lake. As a result, it causes a tremendous increase in the primary productivity of the ecosystem. This leads to an increased growth of algae, resulting into algal blooms. Later, the decomposition of theses algae depletes the supply of oxygen, leading to the death of other aquatic animal life.

2. Biological magnification:
The increase in concentration of harmful non – biodegradable substances into higher tropic level is called biological magnification. DDT used to protect the crops reach the soil and are absorbed by plants with water and minerals from the soil. Due to rain, these chemicals can also enter water sources and into the body of aquatic plants and animals.

As a result, chemicals enter the food chain. Since, these chemicals cannot be decomposed, they keep on accumulating at each trophic level. The maximum concentration is accumulated at the top carnivore’s level. The producers (phytoplankton) were found to have 0 04 ppm concentration of DDT.

Since many, types of phytoplankton were eaten by zooplankton (consumers), the concentration of DDT in the bodies of zooplankton was found to be 0.23ppm. Small fish that feed on zooplankton accumulate more DDT in their body. Thus, large fish (top carnivore) that feed on several small fish have the have the highest concentration of DDT.

3. Groundwater depletion and ways for its replenishment:
The level of ground water has decreased in the recent years. The source of water supply is rapidly diminishing each year because of an increase in the population and water pollution. To meet the demand of water, water is withdrawn from water bodies such as ponds, rivers, etc. As a result, the source of groundwater is depleting.

This is because the amount or groundwater being drawn for human use is more than the amount replaced by rainfall. Lack of vegetation cover also results in very small amounts of water seeping through the ground. An increase in water pollution is another factor that has reduced the availability of groundwater.

Measures for replenishing groundwater:

• Preventing over-exploitation of groundwater.
• Optimizing water use and reducing water demand.
• Rainwater harvesting.
• Preventing deforestation and plantation of more trees.

Question 3.
Why ozone hole forms over Antarctica? How will enhanced ultraviolet radiations affect us?
Answer:
The ozone hole is more prominent over the region of Antarctica. It is formed due to an increased concentration of chlorine in the atmosphere. Chlorine is mainly released from Chlorofluorocarbons (CFC’s) widely used as refrigerants. The CFC’s release chlorine atoms by the action of UV rays on them. The release of chlorine atoms causes the conversion of ozone into molecular oxygen. One atom of chlorine can destroy around 10,000 molecules of ozone and causes ozone depletion.

• CF₂Cl₂ → CF₂Cl + Cl
• Cl + O_{3 →} ClO + O₂
• ClO + O → Cl + O₂

The formation of the ozone hole will result in an increased concentration of UV – B radiation on the Earth’s surface. UV – B damages DNA and activates the process of skin ageing. It also causes skin darkening and skin cancer. High levels of UV – B cause corneal cataract in human beings.

Question 4.
Discuss briefly the following:

1. Radioactive wastes,
2. Defunct ships and e-wastes,
3. Municipal solid wastes.

Answer:
1. Radioactive wastes:
Radioactive wastes are generated during the process of ‘ generating nuclear energy from radioactive materials. Nuclear waste is rich in radioactive materials that generate large quantities of ionizing radiation such as gamma rays. These rays cause mutation in organisms which often results in skin cancer. At high dosage, these rays can be lethal. Safe disposal of radioactive wastes is a big challenge. It is recommended that nuclear wastes should be stored after pre-treatment in suitable shielded containers, which should then be buried in rocks.

2. Defunct ships and e – wastes:
Defunct ships are dead ships that are no longer in use. Such ships are broken down for scrap metal in countries such as India and Pakistan. These ships are a source of various toxicants such as asbestos, lead, mercury etc. Thus, they contribute to solid wastes that are hazardous to health.

E – wastes or electronic wastes generally include electronic goods such as computers, etc. Such wastes are rich in metals such as copper, iron, silicon, gold, etc. These metals are highly toxic and pose serious health hazards. People of developing countries are involved in the recycling process of these metals and therefore, get exposed to toxic substances present in these wastes.

3. Municipal solid wastes:
Municipal solid wastes are generated from schools, offices, homes and stores. It is generally rich in glass, metal, paper waste, food, rubber, leather and textiles. The open dumps of municipal wastes serve as a breeding ground for flies, mosquitoes and other disease causing microbes. Hence, it is necessary to dispose municipal solid waste properly to prevent the spreading of diseases. Sanitary landfills and incineration are the methods for the safe disposal of solid wastes.

Question 5.
What initiatives were taken for reducing vehicular air pollution.in Delhi? Has air quality improved in Delhi?
Answer:
Delhi has been categorized as the fourth most polluted city of the world in a list of 41 cities. Burning of fossil fuels has added to the pollution of air in Delhi. Various steps have been taken to improve the qualify of air in Delhi

Introduction of CNG (Compressed Natural Gas):
By the order of the Supreme Court of India, CNG powered vehicles were introduced at the end of year 2006 to reduce the levels of pollution in Delhi. CNG is a clean fuel that produces very little unbumt particles.

1. Phasing out of old vehicles
2. Use of unleaded petrol.
3. Use of low – sulphur petrol and diesel.
4. Use of catalytic converters.
5. Application of stringent pollution-level norms for vehicles.
6. Implementation of Bharat stage I, which is equivalent to euro II norms in vehicles of major Indian cities.

The introduction of CNG – powered vehicles has improved Delhi’s air quality, which has lead to a substantial fall in the level of CO₂ and SO₂. However, the problem of Suspended Particulate Matter (SPM) and Respiratory Suspended Particulate Matter (RSPM) still persists.

Question 6.
Discuss briefly the following:

1. Greenhouse gases
2. Catalytic converter
3. Ultraviolet – B

Answer:
1. Greenhouse gases:
The greenhouse effect refers to an overall increases in the average temperature of the earth due to the presence of greenhouse gases. Greenhouse gases mainly consist of carbon dioxide, methane and water vapour. When solar radiations reach the Earth, some of these radiations are absorbed.

These absorbed radiations are released back into the atmosphere. These radiations are trapped by the greenhouse gases present in the atmosphere. This helps in keeping our planet warm and thus, helps in human survival. However an increase in the amount of greenhouse gases can lead to an excessive increase in the Earth’s temperature, thereby causing global warming.

2. Catalytic converter:
Catalytic converters are devices fitted in automobiles to reduce vehicular pollution. These devices contain expensive metals such as platinum, palladium and rhodium that act as catalysts. As the vehicular discharge passes through the catalytic converter, the unbumt hydrocarbons present in it get converted into carbon dioxide and water. Carbon monoxide and nitric oxide released by catalytic converters are converted into carbon dioxide and nitrogen gas (respectively).

3. Ultraviolet – B:
Ultraviolet – B is an electromagnetic radiation which has a shorter wavelength than visible light. It is a harmful radiation that comes from sunlight and penetrates through the ozone hole on to the earth’s surface. It induces many health hazards in humAnswer: UV – B damages DNA and activates the process of skin ageing. It also causes skin darkening and skin cancer. High levels of UV – B cause comeal cataract in human beings.

Question 7.
Describe the diseases caused due to radioactive pollution.
Answer:
Following diseases are caused by radioactive pollution:

1. Leukaemia and Bone cancer – In human beings and other animals, radioactive pollution causes blood and bone cancer.
2. Ageing – The reproductive capacity of organisms is decreased due to radioactive pollution and ultimately causes ageing.
3. Epidemic disease – Radioactive pollution causes the decreased rate of antitoxin production which affects the immune system and results in the production of epidemic diseases.
4. Nervous system and sensory cells become irritated.
5. Radioactive pollution results skin cancer.
6. Mutations also take place due to radioactive pollution.
7. Thyroid cancer is also produced due to radioactive iodine.

Question 8.
Burning of crackers spread pollution in the environment. Explain.
Answer:
Explosive substances are used in crackers. Crackers are burned for celebration but it causes many harms to the living organisms. Some of the harm effects of burning of crackers are as follows:

1. Air pollution – It releases harmful gases such as CO₂, CO, SO₂ etc. into the atmosphere which causes respiratory diseases.

2. Noise pollution – Burning of crackers produces noise which causes noise pollution which effects our hearing capacity, causes headache, increases heartbeat and blood pressure.

3. Water pollution – Waste of burning of crackers are drained into the pond, river with rainwater or through drain which caused harm to aquatic organisms.

4. Soil pollution – Burning of crackers not only produces smoke of harmful gases but its harmful chemicals mixes with soil and pollute it, which makes the soil sterile and reduced growth of plants.

Question 9.
Write an essay on air pollution.
Answer:
Air pollution:
Any change in the composition of air is called pollution. The chief reason of air pollution is the releasing of harmful gas in the environment that affect our eyes, lungs, skins, heart and brain and produce various disorders in them.

Sources of air pollution : Following are the chief sources of air pollution:

1. Human sources:

• Combustion activities
• Industrial activities
• Agricultural works
• Use of solvents
• Activities concerned with atomic energy

2. Natural sources:
Volcano and its lava, ash, dust, smoke of forest fire, winds, cyclone. Decomposition of matters in the swamp water and liberation of methane gas and different compounds of hydrogen from forests plants, various pollen grains etc.

Effects of air pollution:

• Air pollutant like SO₂ enter the soft tissues causing drying of the mouth, scratching throat and smarting eyes.
• Hydrocarbons and many other pollutants are responsible for causing cancer.
• Oxides of carbon, sulphur and nitrogen diffuse into the blood stream to combine with haemoglobin causing reduction in its oxygen carrying capacity. CO severely damages cardiovascular system and disturbs psychometry functions.
• RA.N. inhibits Hill reaction and thus, decreases photosynthetic production of an ecosystem.

Control of air pollution:

• Industrial smokes must be filtered before releasing it into the atmosphere.
• Tree plantation should be increased and deforestation prevented.
• Use of automobiles should be minimized which reduce the nitrogen contents in the atmosphere.
• The use of crude fuels should be avoided and use of high quality fuels should be recommended.
• Nuclear explosions should be avoided.
• Legal control of air pollution.
• Plantation of air purifying plants.
• Development of parks and gardens in cities.

Question 10.
Name the major air pollutants and their individual effects.
Answer:
Major air pollutants and their individual effects are as follows:

1. Carbon monoxide:
|It is highly poisonous gas. On entering blood stream, it combines with haemoglobin to block oxygen transport function. It causes laziness, headache, disturbance of psychometry functions, decrease in visual perception, serious effects on cardiovascular system etc.

2. Sulphur dioxide:
The animals and human population when exposed to SO₂, suffer from respiratory diseases. It causes chest constriction, headache, vomiting and death from respiratory ailments.

3. Hydrogen sulphide:
Its rotten egg like smell cause nausea, irritation in eyes and throat.

4. Nitrogen oxide:
It inhibits cilia action so that soot and dust penetrate far into the lungs and finally resulting respiratory diseases in human beings and animals. In plants, it causing chlorosis.

5. Aerosoles:
These are the chemicals affecting ozone layer of the atmosphere due to which UV rays enter in the atmosphere and causing various diseases in plants and animals.

6. Ammonia:
It inflame upper respiratory passage in human beings. In plants, it inhibits seed germination, destruction of chloroplast and inhibition of the growth of roots and shoots.

7. Hydrogen chloride:
It affects the leaves of the plants, eyes, respiratory organs of animals and human beings.

8. Hydrocarbons:
It causes yellowing of plants, drying of buds, whereas in man and other animals, mucous glands of eyes and nose are irritated.

Question 11.
Write down the methods to control soil pollution.
Answer:
Methods to control soil pollution:
By following methods soil pollution can be prevented:

1. Government should make provisions for latrines and people should not be allowed to litter in open fields.
2. Solid wastes such as tin, copper, iron, glass etc., should not be dumped into soil.
3. The solid wastes should be recycled to form new materials.
4. Fertilizers and pesticides should be judiciously used.
5. Instead of pesticides to kill pests, biological control methods should be adopted.
6. The,excretory waste of man and cattle should be used to prepare biogas.
7. Clean and well covered dustbins should be used in villages and cities.
8. Closed hollow pipes should be used to collect and discharge liquid wastes.
9. To prevent soil erosion, grass and small plants should be grown.
10. Soil management should be adopted.

Question 12.
What are the sources of soil pollution?
Answer:
Sources of soil pollution:

1. Acid rainwater and water from mines are main sources of soil pollution.
2. Mixing of debris, waste products with the soil cause soil pollution.
3. By excessive use of pesticides and fertilizers, pollute the soil.
4. When industrial wastes are discharged in the soil, they also pollute the soil.
5. Heavy metals example Cadmium, Zinc, Nickel, Arsenic etc., are mixed with the soil from mines. These metals are harmful for plants as well as primary and secondary consumers, in a food chain.
6. Bones of dead animals, paper putrified flesh and food, iron, copper, mercury etc., pollute the soil.
7. In our villages and rural areas, where there are no latrines, people go in fields for being at ease. From their stool also the soil is polluted.
8. Insecticides like D.D.T. is very dangerous substance. When these enter the body of consumers from producers, their concentration is increased because these are non – degradable substances. Moreover, these can remain in the atmosphere for upto 15 years.

Question 13.
What is visible spectrum? Write short note on spectrum of solar light and also write effect of UV rays on the living organisms.
Answer:
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelength is called visible light or simply light. It ranges from 390 nm to 760 nm wavelength.

Different spectrum of sunlight (solar light):
Spectrum of sunlight can be divided into three parts :

1. Ultraviolet spectrum – The UV spectrum covers the wavelength range 100 – 390 nm and is divided into three bands. It is invisible.
2. Visible spectrum – It include light of ranges from 390 to 760 nm wavelength.
3. Infrared spectrum – Light ranges 760 nm above is called as infrared ray. It is also invisible.

Effect of UV rays in the living organisms:

1. It make DNA abnormal thus, protein sythesis in the body get effected.
2. It may cause skin cancer.
3. It supress immune system of the body.
4. It causes sunburn and premature ageing of skin.
5. It causes formation of harmful photochemical smog which causes respiratory diseases.
6. It damage eyes.

Question 14.
Explain non – ionising and ionising radiation.
Answer:
Types of radiations on the basis of their action on cells, radiations are of two types :

1. Non – ionising radiations:
These include ultraviolet rays (UV rays; 100-300 nm), these have low penetration capacity. These affect only ‘those cells which absorb them. The cause are as following :

• Sunburn – It includes rupturing of sub – cutaneous blood capillaries, blisters, reddening of skin and injury to stratum germinativum.
• Snow blindness – It damages eyesight due to damage of corneal cells.
• Inactivation of organic bio-molecules and formation of thymin dimer in DNA.
• However they cause cancer, tumor, skin disease, etc.

2. Ionizing radiations :
These include X – rays, cosmic rays and atomic radiations.

These radiations have low wavelengths but high penetration power. These damage the living cells shifting the electron from one to other bio – molecule. Their harmful effects are as follows:

1. Short range effects : These may appear within few days or a few weeks after exposure. The effects include loss of hair, nails, subcutaneous bleeding, metabolic changes, change in proportion of blood cells, dead tissues or death of the organisms in high dose.

2. Long range effects : These appear in several months or even several years after their exposure. These cause tumours, cancers, mutations, genetic deformities, shorter life span and developmental defects.

Question 15.
What are sources of noise pollution? Write any four effects of noise pollution.
Answer:
Sources of noise pollution:
Noise is either natural such as thunder or man – made. The common sources of noise pollution are :

1. Industries such as textile mills, printing-press, engineering establishments, etc.
2. Defence equipment and vehicles such as tanks, artillery and rocket launching explosions, practise firing, etc.
3. Transport vehicles as trains, trucks, buses, two – wheelers, jet planes, etc. and accessory noise produced by horns, sirens.
4. Other applications as dynamite blasting, use of jack hammers, pile drivers, bulldozer, lawn mowers, etc.

Effects of noise pollution:

1. The more acute and immediate effect of noise pollution is impairing of hearing leading to auditory fatigue and may finally lead to deafness.
2. Interference with speech communication.
3. Noise pollution leads to neurosis, anxiety, hypertension, cardiovascular disease, hepatic stress, giddiness.
4. Annoyance leading to ill – temper, bickering, mental disorientation and violent behaviour.
5. The high intensity of noise pollution can cause blood vessels to contract, skin becomes pale, muscles to contract and adrenaline to be shot into blood stream with consequence rise in blood pressure. This ultimately results in tension and nervousness.
6. Affects different metabolic activities.

Question 16.
What is Greenhouse effect? Write any four impacts of Greenhouse effect
Answer:
Greenhouse effect:
The Greenhouse effect may therefore, be defined as “The progressive warming up of the earth’s surface due to blanketting effect of man – made CO₂ in the atmosphere. It means the excessive presence of those gases blocked in the infrared radiation from earth’s surface to the atmosphere leading to an increase in temperature, which in turn would make life difficult on earth to forthcoming future generations.

Four impacts of Greenhouse effects are :

1. Effect on global climate:
The climate of earth has never been free of change. Its composition, temperature and self – cleansing ability have all varied since, the planet first formed. Yet the pace in the past two countries has been remarkable. The atmosphere’s composition in particular has changed significantly faster than it has at any time in human history.

Increase in Greenhouse gases does not increase the temperature of the earth i. e., it is not uniform. Temperature is normal at poles and is very less at tropics. In Iceland, Greenland, Sweden, Norway, Finland, Alaska, Siberia, temperature is more, thus at poles, ice starts melting.

2. Effect of Greenhouse Effect on forests:
When the atmospheric temperature increases, only those plants can survive which can bear high temperature. Because of this, new species of plant also come into existence, Herbaceous plant can not survive in this high temperature. Plants with high wood will increase in number. According to a survey if the amount of CO₂ in the atmosphere is doubled, there will be a great decrease in a green biomass.

3. Effect on crops:
The positive aspect of greenhouse effect will be on agriculture. Because, CO₂ is a natural fertilizer, the plants will grow larger and faster with increasing CO₂ in the atmosphere. At first sight, the abnormal growth of plants might be expected to be beneficial because the yields of major crops might increase, however chances of depletion of characters and productivity of soil are also associated with this.

4. Effect on ozone layer:
During depletion, the chlorine, fluorine, or bromine molecules of CFCs and halogens are converted into reactive free radical form by photochemical reactions from their intial non – reactive sites. Oxides of nitrogen generally inactivate Cl but the lowering of stratospheric temperature changes NO₂ into non – reactive nitric acid. Thus, Cl or F are free to react with ozone, distintegrating it into O₂ + O. The tiny ice particles during winter favours the conversion of chlorine into chlorine monoxide, which behaves as a catalytic compound. The abundance of chloromonoxide rich air in stratosphere continues to rise. Chlorine monoxide react with nascent oxygen and thereby gets converted into chlorine. Thus, the cycle continues destroying the ozone level.

MP Board Class 12th Biology Important Questions

MP Board Class 12th Biology Important Questions Chapter 15 Biodiversity and Conservation

Biodiversity and Conservation Important Questions

Biodiversity and Conservation Objective Type Questions 

Question 1.
Choose the correct answer:

Question 1.
Tera biodiversity is used for the first time by :
(a) V. G. Rosseu
(b) Linnaeus
(c) Odum
(d) Theophrastus.
Answer:
(a) V. G. Rosseu

Question 2.
When does wild life conservation Act come in the force in India :
(a) 1883
(b) 1972
(c) 1973
(d) 1972
Answer:
(b) 1972

Question 3.
When does IBWL is started :
(a) 1952
(b) 1981
(c) 1973
(d) 1972
Answer:
(a) 1952

Question 4.
Where is NBPR is situated :
(a) Delhi
(b) Kolkata
(c) Lucknow
(d) Mumbai
Answer:
(a) Delhi

Question 5.
The number of biosphere reserves in India is :
(a) 73
(b) 7
(c) 416
(d) 23
Answer:
(b) 7

Question 6.
Which National Park is associated with white tiger:
(a) Kanger
(b) Satpura
(c) Bandhavgarh
(d) Kanha
Answer:
(c) Bandhavgarh

Question 7.
First National Park of M. P. is :
(a) Shivpuri
(b) Bandhavgarh
(c) Kanha
(d) Kanger
Answer:
(c) Kanha

Question 8.
Where is “Plant Fossil” National Park is situated:
(a) Shivpuri
(b) Mandala
(c) Bastar
(d) Bhopal
Answer:
(b) Mandala

Question 9.
The National Park of M.P. which is marked as biosphere reserve is :
(a) Kanha
(b) Shivpuri
(c) Bandhavgarh
(d) Satpura.
Answer:
(b) Shivpuri

Question 10.
First Tiger Project of M.P. is :
(a) Bandhavgarh
(b) Kanha
(c) Sidhi
(d) Shivpuri.
Answer:
(b) Kanha

Question 2.
Fill in the blanks :

1. FRI is situated is …………………….
2. Kanjiranga sanctuary is associated with the conservation of …………………….
3. Red data book is related with the ……………………. conservation.
4.  ……………………. is the fust biosphere reserve of India.
5. List of the endangered species are available in ……………………. data book.
6.  ……………………. is the important componant of air for life.
7. Mineral is the example of ……………………. sources.
8. ……………………. percent part of the earth has water.
9. Biodiversity is the source of different types of …………………….
10. Species for which there are no living representative is called …………………….
11. Farming which is develop in fresh water is called …………………….
12. Botanical garden is an ……………………. method of plant conservation.
13. ……………………. conservation is the on site conservation.
14. ……………………. percent part of the mangrove plant are found in India.
15. Gir national park in India is famous for …………………….

Answer:

1. Dehradun
2. Rhinoceros
3. Endangered species
4. Nilgiri
5. Red
6. Oxygen
7. Non – renewable
8. 71
9. Germplasm
10. Extinct
11. Aquatic culture
12. Ex – situ
13. In – situ
14. 5
15. Asiatic lion.

Question 3.
Match the followings:
I.

Answer:

1. (b)
2. (c)
3. (d)
4. (a)

II.

Answer:

1. (d)
2. (a)
3. (b)
4. (e)
5. (c)

Question 4.
Write the answer in one word/sentences:

1. Where does Kanha National Park situated?
2. From which person Chipko movement is associated?
3. When does Wild life Conservation Act is emenced in force?
4. How many percent contribution of India is in world’s biodiversity?
5. How many species are found in India?
6. Which are known as the lungs of the earth?
7. How many national park in India?
8. How many wild 1 ife sanctuary in India?
9. What is the basic component of biodiversity?
10. Write the full name of IUCN.
11. Which are most helpful in nature balancing?
12. How many species of bamboo found in India?
13. Name any one book associated with the conservation of wild life.
14. Upper surface of the land is called.

Answer:

1. M.P
2. Sunder Lai Bahuguna
3. 1972
4. 8.1%
5. 1200 species
6. Amazon – rain forest
7. 90
8. 448
9. Gene
10. International Union for conservation of nature and natural resourses
11. Wild animal
12. 100 (about)
13. Red data book
14. Soil.

Biodiversity and Conservation Very Short Answer Type Questions

Question 1.
Name the three important components of biodiversity.
Answer:
Three important components of biodiversity are:

1. Genetic diversity.
2. Species diversity.
3. Ecosystem diversity.

Question 2.
What is forest?
Answer:
A large area of land covered with trees, shrubs and grasses.

Question 3.
As which day 21st March is observed?
Answer:
21st March is observed as “World Forest Day”.

Question 4.
What are extinct species?
Answer:
Species which are not found at present in the earth but survived in the past in this world are called as extinct species.
Example : Dinosaur.

Question 5.
What are mentioned in the Red Data Book of IUCN?
Answer:
The IUCN Red Data Book contains list of threatened species. It was founded in 1964. Correction was done in 2004.

Biodiversity and Conservation Short Answer Type Questions

Question 1.
How do ecologists estimate the total number of species present in the world?
Answer:
The diversity of living organisms present on the earth is very vast.According to an estimate by researchers, it is about seven millions. The total number of species present in the world is calculated by ecologists by statistical comparison between a species richness of a well studied group of insects of temperate and tropical regions. Then, these ratios are extrapolated with other groups of plants and animals to calculate the total species richness present on the earth.

Question 2.
The species diversity of plants (22 %) is much less than that of animals (72 %). What may be the reason that animals achieved greater diversifications?
Answer:
Animals have achieved greater diversification than plants due to following reasons:

1. They are mobile and thus, can move away from their predators or unfavourable, environments. On the other hand plants are fixed and have fewer adaptations to obtain optimum amount of raw materials and sunlight therefore, they show lesser diversity.

2. Animals have well developed nervous system to receive stimuli against external factors and thus, can respond to them. On the other hand, plants do not exhibit any such mechanism, thus they show lesser diversity than animals.

Question 3.
Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
Answer:
Yes, there are various kinds of parasites and disease causing microbes that we deliberately want to eradicate from the earth. Since, these microorganisms are harmful to human beings, scientists are working hard to fight against them. Scientists have been able to eliminate smallpox virus from the world through the use of vaccinations. This shows that humans deliberately want to make these species extinct. Several other eradication programmes such as polio and hepatitis B vaccinations are aimed to eliminate these disease causing microbes.

Question 4.
Explain conservation of biodiversity.
Answer:
Conservation of biodiversity:
India is one of the richest (among the 12 mega centres of the world) countries in biological diversity. This rich biodiversity is due to a variety of climatic conditions prevailing on different ecological habits ranging from tropical, subtropical, temperate, alpine to desert. These varied conditions harbour a plethora of organisms, which forms an important natures wealth, responsible for socio – economic development of life in our country. But the biodiversity of organisms are under serious threat and there is an urgent need for biodiversity conservation on war foot level.

Question 5.
What is social forestry?
Answer:
The planning of social forestry started in India since 1976, which is related with the conservation of forests. This project ;s useful for local people in various ways, such as it fulfil their requirements, provides work to unemployed, use of wasteland and help to maintain O₂ and CO₂ balance in the atmosphere, etc. Thus, project is started by Indian government, the chief objectives of this project are as follows:

1. Plantation of useful plants in the forest.
2. Development of forests on personal lands by the cooperation of government.
3. To prevent the harmful effects of pollution by development of artificial forest.
4. Preservation of endangered wild animals.

Question 6.
Write importance of forests.
Answer:
Importance of forests:

1. Forests play a vital role in the life and economy of all tribes living in forests, by providing food, medicines and other products of commercial value.

2. Forests are large biotic communities. It provides shelter and sustenance to a larger number of diverse species of plants, animals and microorganisms.

3. Forests prevent soil erosion by wind and water. The trees provide shade which prevents the soil from drying during summer. Trees reduce the velocity of raindrops or wind striking the ground so that dislodging of the slil partiles is reduces. The root system of plants firmly binds the soil.

Question 7.
Write any five features of Indian forests.
Answer:
Indian forests are characterized by:

1. Indian forests are mainly tropical forests.
2. Himalayan forests are characterized by the presence of coniferous trees.
3. In few parts of our country having temperate forests.
4. Our forests contain a large number of useful varieties of plants and animals.
5. A great variations are present in Indian forests.

Question 8.
Enumerate any five reasons for the destruction of wildlife (animals).
Answer:
The main reason of destruction of wildlife (animals) are:

1. Entertainment, personal profit, earning money by wrong methods are the human illattitudes, unkindness toward wild animals has brought the animals at endanger level.
2. Huge reduction in the natural habitat of wild animal so it has reduced their living area due to urbanization, industrialization and deforestation.
3. Exhorbitant extraction and consumption is harmful for wild animals like skin of animals, Teeth of elephant etc.
4. Various types of pollution has force the reduction of wild animals.
5. Very loose and unpunishable wildlife act which has increase poaching, hunting of wild animals.

Question 9.
How is biodiversity important for functioning of ecosystem?
Answer:
An ecosystem with high species diversity is much more stable than an ecosystem with low species diversity. Also, high biodiversity makes the ecosystem more stable in productivity and more resistant towards disturbances such as alien species invasions and floods. If an ecosystem is rich in biodiversity, then the ecological balance would not get affected.

Various tropic levels are connected through food chains. If any one organism or all organisms of any one trophic level is illed, then it will disrupt the entire food chain. For example, in a food chain, if all plants are killed, then all deer’s will die due to the lack of food. If all deer’s are dead, soon the tigers will also die.

Therefore, it can be concluded that if an ecosystem is rich in species, then there will be other food alternatives at each trophic level which would not allow any organism to die due to the absence of their food resource. Hence, biodiversity plays an important role in maintaining the health and ecological balance of an ecosystem.

Question 10.
What are sacred groves? What is their role in conservation?
Answer:
Sacred groves are forest patches for worship in several parts of India. All the trees and wildlife in them are again treated and given total protection. They are found in khasiandjointia hills in Meghalaya. Western Ghat regions of Karnataka and Maharashtra, etc. Tribals do not allow anyone to cut even a single branch of tree in these sacred groves thus, sacred groves have been free form all types of exploitations.

Question 11.
Among the ecosystem services are control of floods and soil erosion, how is this achieved by the biotic components of the ecosystem?
Answer:
Control of soil erosion:
Plant roots hold the soil particles tightly and do not allow the top soil to be drifted away be winds or moving water. Plants increase the porosity and fertility of the soil.

Control of floods:
It is carried out by retaining water and preventing run off rain water. Litter and humus of plants function as sponges thus, retaining the water which percolates down and get stored as underground water. Hence, the flood is controlled.

Question 12.
Give three hypothesis for explaining why tropics show greatest levels of species richness.
Answer:
There are three different hypothesis proposed by scientists for explaining species richness in the tropics:

1. Tropical latitudes receive more solar energy than temperate regions, which leads to high productivity and high species diversity.
2. Tropical regions have less seasonal variations and have a more or less constant environment. This promotes the niche specialization and thus, high species richness.
3. Temperate regions were subjected to glaciations during the ice age, while tropical regions remained undisturbed which led to an increase in the species diversity in this region.

Biodiversity and Conservation Long Answer Type Questions

Question 1.
What is the significance of the slope of regression in a species – area relationship?
Answer:
The slope regression (z) has a great significance in order to find a species – area relationship. It has been found that in smaller areas (where the species-area relationship is analyzed), the value of slopes of regression is similar regardless of the taxonomic group or the region. However, when a similar analysis done in larger areas, then the slope of regression is much steeper.

Question 2.
What are the major causes of species loss in a geographical regions?
Answer:
The following are the major causes for the loss of biodiversity around the world:

1. Habitat loss and fragmentation:
Habitats of various organisms are altered or destroyed by uncontrolled and unsustainable human activities such as deforestation, slash and burn agriculture, mining, and urbanization. This results in the breaking up of the habitat into small pieces, which effects the movement of migratory animals and also, decreases the genetic exchange between populations leading to a declination of species.

2. Over – exploitation:
Due to over – hunting and over – exploitation of various plants and animals by humans, many species have become endangered of extinct (such as; the tiger and the passenger pigeon).

3. Alien species invasions:
Accidental or intentional introduction of non-native species into a habitat has also led to the declination or extinction of indigenous species. For example, the Nile perch introduced in Lake Victoria in Kenya led to the extinction of more than two hundred species of native fish in the lake.

4. Co – extinction:
In a native habitat, one species is connected to the other in an intricate network. The extinction of one species causes the extinction of other species, which is associated with it in an obligatory way. For example, the extinction of the host will cause the extinction of its parasites.

Question 3.
What do you understand by Threatened species? Explain its types.
Answer:
Species which have been greatly reduced in their number or whose natural habitats have been, disturbed due to which these are near extinction and may become extinct if the causative factors continue are called threatened species. It is estimated that about 25,000 plant species and 1,000 vertebrate species and subspecies and many invertebrate species are threatened with extinction. It is believed that at least 10% of the living species are in danger.

The organisms which are near extinction are of following types:

1. Endangered (E) species:
The species which are facing danger of extinction and whose survival is unlikely if the causal factors continue to operate. These are the species whose number have been reduced to a critical level or whose habitats have been so drastically reduced that they are deemed Lto be in immediate danger of extinction. For example, Indian rhinoceros, Asiatic lion and the great Indian bustard, snow leopard etc.

2. Vulnerable (V) species:
These are the species having sufficient number of individuals in their natural habitats. However, in the near future, they might represent the category of endangered species if unfavourable factors in the environment continue to operate, e.g., Musk deer, black buck, golden langur, etc.

3. Rare (R) species:
These are species with small population in the world. At present these are not endangered and vulnerable but are at risk. These species are usually localize within geographical areas or habitats or are thinly scattered over a more extensive range, e.g., Indian elephant, Asiatic wild ass, gharial, wild yak etc.

4. Threatened (T) species:
The species which do not fall under the endangered or vulnerable categories but indications are available that such species may come under any of these two categories if appropriate measures are not taken to protect them.

Question 4.
What are National Parks? Explain any five National Parks found in India.
Answer:
National Park:
Natinal park is an area which is strictly reserved for the betterment of the wildlife and where activities like forestry, grazing or cultivation are not permitted.

Five national parks of India are:

1. Shivpuri national park – It is located at Shivpuri near Gwalior (Madhya Pradesh). Wildlife present in this park tiger, cheetal, sambhar.
2. Guindy deer national park – It is located near Chennai (Madras) in Tamil Nadu. Wildlife found here ore Alvino deer, black buck, cheetal and famous snake park.
3. Betla national park – It is located in Palamu at Bihar. Wildlife found in this national park are elephant, tiger.
4. Dachigham national park – It is located at Srinagar in Jammu and Kashmir. Wildlife leopard, black beer, brown bear, musk deer, hangul, scrow, etc.
5. Bandhavgarh national park – It is located at Shahdol in Madhya Pradesh. Wildlife such as white tiger, panther, cheetal, bison, nilgai, barking deer, wild boar, etc. are found here.

Question 5.
Write in brief, the reasons necessary for conservation of wild species.
Answer:
Necessity for wildlife conservation : The conservation of wildlife is required for the following reasons :

1. To maintain balance in nature:
The wildlife helps us in maintaining the balance of nature. Once this equilibrium is disturbed it leads to many problems. The destruction of carnivores or insectivores often leads to an increase in the herbivores which in turn affects the forest vegetation or crop.

2. Economic value:
The wildlife can be used commercially to earn money example Animal products like hides, ivory, fur etc. are of tremendous economic value. The collection and supply of dead or living specimens of wildlife for museums and zoos fetches good amount of money. Wildlife can increase our earning of foreign exchange if tourism is promoted properly.

3. Scientific value:
The preservation of wildlife helps many naturalists and behaviour biologists to study morphology, anatomy, physiology, ecology and behaviour biology of the wild animals under their natural surroundings.

4. Recreational value:
The wildlife of any country provides best means of sports and recreation. Bird – watching is a hobby of many people all over the world. A visit to the parks and sanctuaries is an enjoyable proposition for children as well as for adults.

5. Cultural value:
The wildlife of India is our cultural asset and has deep rooted impact on Indian art, sculpture, literature and religion. Indus valley civilization shows the use of animals symbols in their seals.

6. Preservation of human race:
The destruction of wildlife in an area may eventually lead to the end of human civilization.

Question 6.
Describe the National and International efforts prescribed for the conservation of forests.
Answer:
The forest conservation is started in India on national level since British government. In 1856, Lord Dalhousi had formulated a policy for the conservation of forest in Burma. In 1894, Indian government also prepared a forest policy on national level. The main points of this policy are:

1. Forest management
2. Proper use of forest land
3. Polity for, protected forests
4. Improved forest production

Indian government established national parks, sanctuaries and zoological parks, The F.A.O. of United Nations is also functioning on forest conservation on international level. This organization also provides financial help for this purpose. In 1952, Indian government also prepared India’s New National Forest Policy under the direction of F.A.O. Forest policy has been planned for :

1. Prevention of deforestation of hill plants.
2. Reforestation of grazing land.
3. Development of grazing land.
4. Plantation of economically useful forest trees.
5. Increase in the profit of government from forests.

Question 7.
Write a short note on wild animals in India.
Answer:
India as a country has a diverse range of wildlife. India is home for many species of wild animals. More than 25% land are dense forest in India and around 400 national parks. Some of the most important and popular wild animals in India are as follows:

(A)
Animals : In Indian forest, below mentioned animals are found:

1. Deer – Its many species are found in India example Musdeer, Sambhar deer, chital, etc.

2. Antelope – These are same as deer example Nilgai, Barasingha (Swamp deer), four homed antelope (Chousingha) etc.

3. Elephant – Elephants are large mammals of the family elephantidae. It is found in Kerela and North India.

4. Rhinoceros – It is found in Himalaya region and in the forest of Bengal and Assam. Humans are the biggest threat to the Indian rhinoceros as the have been hunted to the brink of extinction for their horns.

5. Wild Ass – Wild asses are not found in any part of the world. Now in India, it is found in the little Rann of Kutch in the Gujarat state of India.

6. Carnivorous animals – Some Indian wild carnivores are:

• Indian lion (Asiatic lion) : Now it is confined to forests in the fall.
• Cheetah : It is on the verge of extinction.
• Lion : Lion is a national animal, at present its population in our country are more than 3,000.
• Leopard : It is similar to cheetah but smaller than cheetah.

(B)
Birds:
Peacock, wild fowl, many types of duck, stork, pigeons, partridge, quail, vulture, kite, piquant, owl, indian paradise flycatcher (dudhraj) are found in forests of our country.

(C)
Reptiles:
Crocodiles, alligators, tortoise, lizards, snakes and other reptilians are found in Indian forest. Many vertebrates and invertebrates are also found in Indian forest.

Question 8.
What are the main rules of Indian forest act?
Answer:
The Indian Forest Act, 1927 was largely based on previous Indian forest acts implemented under the British. Things which are included in this act are as follows:

1. Forest arrangement – Due to this Act, give the protection and arrangement to forest and Midlife.
2. Appropriate use of forest land – Uses of extra land for forest animals and grow some plant these are useful in wild animals.
3. Act for protection of forest – This act, stop passion of deforestation and must be conservation of forest and wild animals.
4. Increasing of forest product – Due to this act try to increasing of forest product and discovered new information which are better for wildlife.

Question 9.
Write an essay on measures of forest conservation.
Answer:
Forest conservation:
Forest conservation and management are essential to maintain the forests in their natural state and also to prevent the depletion of wildlife and forest wealth. For the success of conservation it is necessary to know the cause of depletion and destruction of forests. Forests are generally destroyed by fire, improper cutting of trees and by animals.

Essentiality of forest conservation:
Forest is a complex system which is responsible for the ecological balance in nature. Deforestation causing natural imbalance and affects the biotic components of the environment resulting floods, drought, epidemics, environmental pollution. Many ecologically important species of plants and animals are lost due to which economically important substance like wood, medicines, resin, lac and various food materials will not be available for us.

Measures of forest conservation : The following measures or efforts are prescribed for reforestation:

1. Establishment of conserved forests and their conservation in proper way.
2. Reforestation on deforested land. Old and damaged plants would be replaced by new plants.
3. Proper management of forests.
4. By promoting public awareness about forests.
5. Replacement of burnt off areas of the forests.
6. Plantation of trees that increase forest productivity.
7. Forestation of plants on hills and wastelands and prevention of grazing by cattle.
8. Prevent forests from fire, diseases and insects.
9. Providing basic protection for all forests by law.
10. Regulating human activity in the forest such as grazing by cattle and collection of firewood and fodder etc.
11. Provide special attention for the conservation of endangered plant and animal species under the inspection of specialists.
12. Removal of undesirable trees and vegetation for the better growth of desirable species.
13. Forestation of industrially useful plants.
14. The government will arrange the management of useful forests.

MP Board Class 12th Biology Important Questions