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MP Board Class 11th Chemistry Important Questions Chapter 9 Hydrogen

Hydrogen Important Questions

Hydrogen Very Short Answer Type Questions

Question 1.
In which compound the oxidation state of hydrogen is negative?
Answer:
CaH₂.

Question 2.
The bleaching property of H₂O₂ is due to oxidation or reduction?
Answer:
H₂O₂ easily gives oxygen therefore, it is used as bleaching agent. This is due to oxidation property it is used in bleaching.
H₂O₂ → H₂O + [O].

Question 3.
Who discovered hydrogen?
Answer:
Henry Cavendish.

Question 4.
What is used as moderator in atomic reactors?
Answer:
Heavy water (D₂O).

Question 5.
H₂O₂ reduces Cl₂ in which compound?
Answer:
In HCl.

Question 6.
The bleaching property of H₂O₂ depends upon?
Answer:
Oxidation.

Question 7.
Which oxide forms H₂O₂ with dii. HCI?
Answer:
Na₂O₂ and BaC₂.

Question 8.
Why the vapourisation of ethanol takes place faster than water?
Answer:
Due to weak hydrogen bonding.

Question 9.
Which type of compounds formed lattice carbides?
Answer:
d and f – block elements.

Question 10.
What is the use of lattice hydrides?
Answer:
For storage of H₂ and to catalyze the hydrogenation reaction.

Question 11.
Which acts as propellant in rockets?
Answer:
H₂O₂ (Hydrogen peroxide).

Question 12.
What is known as the absorbtion of hydrogen by palladium?
Answer:
Absorption.

Question 13.
Which chemical compound is called calgon?
Answer:
Sodium hexa metaphosphate.

Question 14.
What is main difference between ortho and meta hydrogen?
Answer:
Nuclear Spin.

Question 15.
What is prepared by the combustion of kerosene?
Answer:
Oil gas.

Question 16.
What is used as trace to study the processes occuring in organisms?
Answer:
Heavy water.

Question 17.
What is the radioactive isotope of hydrogen?
Answer:
Tritium.

Question 18.
What is formed by the reaction of calcium phosphate with water?
Answer:
Phosphene.

Question 19.
What is the bond angle in H – O – O in H₂O₂?
Answer:
97°.

Question 20.
Which hydrides are not in simple proportion?
Answer:
Interfacial hydrides.

Hydrogen Short Answer Type Questions – I

Question 1.
What is the reason for the temporary and permanent hardness of water? Explain?
Answer:
The temporary hardness of water is due to calcium and magnesium carbonate and the permanent hardness is due to presence of calcium chloride, magnesium chloride, calcium sulphate and magnesium sulphate.

Question 2.
Write an expression to show the amphoteric nature of water?
Answer:
Water has amphoteric nature. It behaves both as acid and base. With strong acid it behaves as base and with strong bases it behaves as acid.

Question 3.
How the impure hydrogen is purified?
Answer:
When hydrogen gas is passed on platinum black or palladium metal, the hydrogen gas is adsorbed this is called adsorption. The impure hydrogen gets purified.

Question 4.
Write the disadvantages of hard water?
Answer:

1. Hard water cannot be used in laboratory and for injection in medical.
2. Much quantity of soap is wasted if clothes are cleaned with hard water due to the formation of insoluble calcium and magnesium soap.
3. Hard water is unuseful in dyeing and printing.
4. Cooking with hard water take longer time and spoil the taste and quality of food.

Question 5.
Explain the Lane’s method to prepare hydrogen?
Answer:
By passing alternate currents of steam and water gas over red hot iron. The oxidation and reduction processes are alternatively carried out.

Oxidizing stage:
Superheated steam is passed over red hot iron at about 1023 K and 1073K, hydrogen gas is produced and magnetic oxides of iron (Fe₃O₄) is left.
3Fe + 4H₂O → Fe₃O₄ + 4H₂↑.

Question 6.
Write the method of removal of permanent as well as temporary hardness of water?
Answer:
By adding washing soda (Na2C03) when permanent hard water is treated with calculated quantity of sodium carbonate solution calcium and magnesium salts present in water get precipitated as insoluble carbonate. Soft water is then decanted off.
CaCl₂ + Na₂CO₃ → CaCO₃ + 2NaCl
MgSO₄ + Na₂CO₃ → MgCO₃ + Na₂SO₄
MgCl₂ + Na₂CO₃ → MgCO₃ + 2NaCl
CaS0₄ + Na₂CO₃ → Na₂SO₄ + CaCO₃.

Question 7.
How the strength of H₂O₂ is expressed?
Answer:
Strength of Hydrogen Peroxide Solution:
The strength of hydrogen peroxide solution is expressed in terms of the volume of oxygen obtained from it. For example, 10 volume, 20 volume etc. (MPBoardSolutions.com) The strength is equal to the volume of oxygen produced at NTP which is obtained by heating one unit of that solution. The ‘10 volume’ solution of hydrogen peroxide will give 10 ml oxygen at NTP when 1 ml of the sample is heated.

Question 8.
Write the uses of hydrogen?
Answer:
Uses of hydrogen:

1. As a reducing agent.
2. On account of its lighter nature, it was previously used in filling of balloons and aeroplanes but due to its combustible nature, a mixture of inert gas helium (85%) and hydrogen (15%) is used now.
3. In the manufacture of methyl alcohol, ammonia, synthetic petrol and fertilizers.
4. For preparing vegetable ghee: Hydrogenation of vegetable oil gives vegetable ghee.
5. Oxyhydrogen flame: Hygrogen produces high temperature when bums with oxygen which is used for welding and cutting purposes.
6. Hydrogen is used as a rocket propellent.

Question 9.
What is the difference between the terms “hydrolysis” and “hydration”?
Answer:
Hydrolysis:
Hydrolysis is the interaction of H⁺ and OH^– ions of water with the anion and cation of salt respectively to form acid and base.
Example:

Hydration:
Hydration is the interaction of water with the salts to form co – ordinated or hydrated ions or hydrated salts.
Example:
1. Water molecules are co-ordinated to metal ion in a complex.
[Cr(H₂O)₆]Cl₃.

2. Water occupying interstitial sites in the crystal lattice.
BaCl₂.2H₂O.

Question 10.
What is oil gas? How it is prepared?
Answer:
Coal gas is a mixture of many gases. When a thin layer of kerosene is dropped on red hot retort, then big molecules break and converts into methane, ethylene, acetylene. It is used in burners.

Question 11.
What is coal gas? Write its constituent?
Answer:
Coal gas is mixture of many gases where hydrogen gas is main element.
H₂ = 43.55%, N₂ = 2.12%, CH₄ = 25.35%, CO₂ = 0.3%, CO = 4.11%, O₂ = 0 – 1.5%.

Question 12.
When sodium reacts with water, which gas is released? Write name and formula?
Answer:
The more reactive metals (Na, K, Ca) react with water and metal hydroxide are formed and H₂ gas is released.
2Na + 2H – OH → 2NaOH + H₂↑
Ca + 2H – OH → Ca(OH)₂ + H₂↑
2K + 2H – OH → 2K—OH + H₂↑.

Question 13.
Write the reason for hardness of water and how many types of hardness are there?
Answer:
Water which does not readily produce lather with soap solution and cause of hardness of water. It is due to the presence of bicarbonate, sulphates and chlorides of calcium and magnesium in it. These salts get dissolved in it as it passes through the rock or ground.
Types of hardness:

1. Temporary hardness: It is due to the presence of bicarbonates of calcium, magnesium ion dissolved in water.
2. Permanent hardness: It is due to the presence of chlorides and sulphates of calcium, magnesium and iron in water.

Question 14.
What are hard and soft water?
Answer:
Hard water:
Water which does not readily produce lather with soap solution is known as hard water.
Soft water:
Water which readily produce lather with soap solution is known as soft water.

Question 15.
What is distilled water? Give its one use?
Answer:
The water which is formed with the help of distillation, this water is called distilled water. Its main use is in medicines and to prepare reagents in laboratory.

Question 16.
Write the uses of heavy water?
Answer:
Deuterium oxide is known as heavy water, its chemical formula is D20. It contains two deuterium atom in place of normal hydrogen atom.
Uses of heavy water:
1. Heavy water is used in nuclear reactors to slow down the speed of neutrons to carry out many important reactions. It is also used in the preparation of deuterium D₂. It is employed as a tracer in the study of reactions occurring in living organisms.

2. D₂O is used in atomic reactors where it serves two purposes:

• It acts as a coolant and
• Act as a moderator.

3. The water of some rivers like the Ganga remains clear and pure even when kept for years. It is due to presence of heavy water in it.

Question 17.
Explain the oxidising and reducing nature of H₂O₂?
Answer:
1. H₂O₂ liberates oxygen atom easily so it is strong oxidising agent but when it reacts with other oxidising agent it easily extracts oxygen atom from them hence it possesses reducing property too.
Oxidising nature:

1. PbS + 4H₂O₂ → PbSO₄ + 4H₂O
2. NaNO₂ + H₂O₂ → NaNO₃ + H₂O
3. Na₂SO₃ + H₂O₂ → Na₂SO₄ + H₂O

Reducing nature:

1. H₂O₂ + O₃ → H₂O + 2O₂
2. H₂O₂ + Na₂O₂ → Na₂O + H₂O + O₂
3. Ag₂O + H₂O₂ → 2Ag + H₂O + O₂.

Question 18.
Why the solution H₂O₂ did not concentrated on heating? How it can be concentrated?
Answer:
Hydrogen peroxide obtained by any method is dilute. It cannot be concentrated by boiling because it decomposes at a temperature below its boiling point. Therefore it is concentrated by following step:
1. Evaporation:
Evaporation of dilute solution of H₂O₂ on water bath at 70°C gives 45 – 50% H₂O₂ solution.

2. Vacuum evaporation:
The evaporation is further carried on, in a vacuum desiccator over concentrated sulphuric acid. In this way 66% solution of hydrogen peroxide is obtained.

3. Distillation under reduced pressure:
66% solution of hydrogen peroxide on distillation under reduced pressure, yields hydrogen peroxide of 99% concentration.

4. Crystallization:
H₂O₂ solution obtained in the above step is placed in a freezing mixture of solid CO₂ and ether. Crystals of H₂O₂ formed are separated and melted to obtain pure H₂O₂.

Question 19.
For the manufacture of hydrogen peroxide from peroxides, phosphoric acid is more useful than sulphuric acid why?
Answer:
H₂SO₄ acts as catalyst in the decomposition of H₂O₂. So for the manufacture of H₂O₂ from peroxides instead of H₂SO₄, weak acids like H₃PO₄, H₂CO₃ etc. are more useful.
3BaO₂ + 2H₃PO₄ → Ba₃(PO₄)₂ + 3H₂O₂
insoluble.

Question 20.
An ionic crystal of an alkali metal has significant covalent character and is almost unreactive towards oxygen and chlorine. This is used in the synthesis of other useful hydrides. Write the formula of this hydride? Write its reaction with Al₂Cl₆?
Answer:
The hydride is LiH. Due to Li it behaves as covalent compound. It is highly stable.
8LiH + Al₂Cl₆ → 2LiAlH₄ + 6LiCl

Question 21.
Why hard water does not give fast lather with soap?
Answer:
In hard water bicarbonate, chlorides and sulphates of Ca and Mg are present. Soaps are sodium salt of higher fatty acids e,g., sodium stearate (C₁₇H₃₅COONa). (MPBoardSolutions.com) Salts of calcium and magnesium react and form precipitates of calcium and magnesium stearate.
2C₁₇ H₃₅ COONa + M²⁺ → (CH₁₇ H₃₅ COO)₂ M + 2Na⁺
Until all the salts are precipitated, no lather is formed with soap and this soap is wasted.

Question 22.
Write four uses of H₂O₂?
Answer:

1. It has antiseptic properties and hence used cleaning teeth, ears, wounds, etc.
2. It is used for bleaching hair, silk, wool, feathers, ivory, etc.
3. As oxidizing agent in laboratory.
4. In the preservation of milk, wine and some other drinks.
5. As a rocket fuel (as propellant) by producing oxygen.

Question 23.
Write the method of production of hydrogen from water gas?
Answer:
Process of preparation of hydrogen from water gas is known as Bosch process. Bosch process : In this process, hydrogen is obtained by separating it from water gas. Water gas is produced by passing steam over red hot coke.

Water gas is mixed with steam and heated at a temperature of 450 °C in presence of Fe₂O₃ as catalyst and chromic oxide as promoter when carbon monoxide gets oxidized to carbon dioxide.

The mixture of hydrogen and carbon dioxide is passed through water under 25 atmospheric pressure. Carbon dioxide gets dissolved leaving behind hydrogen. (MPBoardSolutions.com) Hydrogen so obtained still contains some carbon monoxide. It is removed by passing the gas through ammoniacal solution of cuprous chloride. The hydrogen so obtained contains nitrogen as impurity.

Question 24.
What is conducting water? Write their uses?
Answer:
Kohlrausch distilled the water 42 times at low pressure in an aperture made up of quartz. This water is called conducting water. This is used for
conductivity.

Question 25.
Write the redox reaction between fluorine and water?
Answer:
Fluorine is strong oxidising agent. It oxidizes H₂O into O₂ and O₃.
2F_2(g) + 2H₂O_(l) → O_2(g) + 4H⁺_(aq) + 4F^–_(aq) 3F_2(g) + 3H₂O_(l) → O_3(g) + 6H⁺_(aq) + 6F^–_(aq).

Question 26.
Explain why HCI is a gas and HF is a liquid?
Answer:
F is smaller and more electronegative than Cl, so it forms stronger H – bonds as compared to Cl. As a consequence, more energy is needed to break the H – bonds in HF than HCI and hence the boiling point of HF is higher than that of HCI. That’s why HF is liquid and HCI is a gas.

Question 27.
Write an equation for the manufacturing of D₂O₂?
Answer:
On reaction of D₂SO₄ with BaO₂, D₂O₂ is prepared.
BaO₂ + D₂SO₄ → BaSO₄ + D₂O₂

Question 28.
Why H₂O₂ cannot be kept for a longer time?
Answer:
Since hydrogen peroxide decomposes on storage, therefore H₂O₂ is stored in brown bottle to avoid the effect of light. This is because the light cause the decomposition of H₂O₂. (MPBoardSolutions.com) A small quantity of acetanilide is also added which retard the decomposition of H₂O₂. Here acetanilide acts as an inhibitor.

Question 29.
Why H₂O₂ is called Antichlor?
Answer:
In neutral medium H202 reduce halogen to acid, metal oxides to metals and ozone to 02.
Cl₂ + H₂O₂ → 2HCl + O₂
Br₂ + H₂O₂ → 2HBr + O₂.
Due to its ability to reduce chlorine it acts as an Antichlor in bleaching by destroying the unreacted chlorine.

Question 30.
When the temporary hard water is boiled with lime water, it becomes soft Why?
Answer:
This method is called Clark method. When temporary hard water is treated with calculated quantity of lime, bicarbonate present in water change to insoluble carbonates which settle down. Soft water is then decanted off.
Ca(HCO₃)₂ + Ca(OH)₂ → 2CaCO₃ + 2H₂O
Mg(HCO₃)₂ + Ca(OH)₂ CaCO₃ + MgCO₃ + 2H₂O

Question 31.
Do you expect the carbon hydrides of the type (C_n H_2n+2) to act as Lewis acid or base? Justify your answer?
Answer:
C_nH_2n+2 such as CH₄, C₂H₆ etc. neither act as Lewis acid nor Lewis base. It is because octet of all the carbon atoms are completed.

Question 32.
Explain the effect of high enthalpy of H – H bond on reactivity of dihydrogen?
Answer:
Due to high enthalpy of dissociation of H – H bond. Hydrogen is unreactive at room temperature. But at high temperature and in presence of catalyst it forms hydrides with metals and non – metals.

Question 33.
In which compound the oxidation number of hydrogen is negative?
Answer:
When hydrogen reacts with higher metal or highly reactive metals like Na, K, Ca etc then electrovalent hydrides are formed. In this hydride the hydrogen has negative oxidation state.

Hydrogen Short Answer Type Questions – II

Question 1.
What is deuterium? Write its two uses?
Answer:
Deuterium is obtained by electrolysis of heavy water. It is collected at cathode and shows reaction similar to hydrogen like its form heavy ammonia (ND₃) with nitrogen heavy water (D₂O) with oxygen.

Uses:

1. Chemical and Biological reaction.
2. It is used in artificial transmutation as target particle.

Question 2.
Give reason:

1. Lakes freeze from top towards bottom.
2. Ice floats on water.

Answer:

1. Water has maximum density at 4°C. In severe cold, the surface of the lake almost freezes but below the surface, there is water at a temperature about 4°C. This property is extremely helpful for animals living under lake water.
2. Ice floats on liquid water as its density is less than liquid water.

Question 3.
If same mass of liquid water and a piece of ice is taken, then why is the density of ice less than that of liquid water?
Answer:
The mass per unit volume (i.emass/volume) is called density. Since water expands on freezing, therefore, volume of ice for the same mass of water is more than liquid water. In other words, density of ice is lower than liquid water and hence ice floats on water.

Question 4.
How is the detection of hydrogen peroxide is performed?
Answer:
Test for hydrogen peroxide:

1. When few drops of H₂O₂ is added to acidified potassium dichromate solution containing ether, blue colour solution is formed which confirms the presence of H₂O₂.
2. Titanium dioxide is mixed with hot and cone. H₂SO₄ and then cooled followed by addition of few drops of hydrogen peroxide, yellow – orange pertitanic acid is produced.
3. On adding few drops of H₂O₂ to acidified glycol solution, blue colour is obtained.
4. Addition of few drops of H₂O₂ to a solution of FeSO₄ and starch and potassium iodide solution gives blue colour.
5. Addition of few drops of H₂O₂ to a mixture of aniline and potassium chlorate in dilute sulphuric acid give violet solution.

Question 5.
On the basis of electronic configuration justify the position of hydrogen in periodic table?
Answer:
Hydrogen is the first and the lightest element of the periodic table. It is not a metal but a non – metallic element. But on the basis of electronic configuration it is kept in first group of 5 – block. It is found in atomic form only at high temperature. (MPBoardSolutions.com) In elemental form it is found as diatomic molecule i.e., as H₂ and is also called as dihydrogen. One proton and one electron is found in hydrogen atom. Hydrogen forms large number of compounds and is an element of high industrial importance.

Hydrogen is the first element of periodic table with one proton in the nucleus and one electron in the first shell (K – shell). It is not possible to assign a to hydrogen in Mendeleev’s and modem periodic table because it shows similarities and dissimilarities with alkali metals (IA group), halogens (VIIA group) and carbon group (IV A group). This makes position of hydrogen very controversial. Because of this it is also known as Rogue element.

Question 6.
H₂O₂ is used for shining the old oil paintings?
Answer:
Old oil paintings contain basic lead oxide, H₂S present in atmosphere change lead oxide into lead sulphide. Thus, white paintings become black.

When the paintings are washed with hydrogen peroxide black lead sulphide oxidised into lead sulphate and painting shine again.

Question 7.
Draw the atomic structures of all isotopes of hydrogen?
Answer:
Atoms of an element having same atomic number but different atomic mass is known as isotope. Hydrogen has three isotopes :

1. Protium or ordinary hydrogen \(_{ 1 }^{ 1 }\)H
2. Deuterium or heavy hydrogen \(_{ 1 }^{ 1 }\)H
3. Tritium or radioactive hydrogen \(_{ 1 }^{ 3 }\)H

Structural diagram:

Isotopic effect:
The difference in properties mass is called isotopic effect.

Question 8.
On the basis of structure and chemical reactions? Explain, what are the characteristics of electron deficient hydrides?
Answer:
Electron deficient hydrides do not have sufficient number of electrons to form normal covalent bonds. They generally exist in polymeric forms such as B₂H₆, B₄H₁₀, (AlH₃)_n etc.
Due to deficiency of electrons, these hydrides act as Lewis acids and thus, form complex entities with Lewis bases such as NH₃, H^– ions.
B₂H₆ + 2NH₃ → BH₂(NH₃)₂]⁺(BH₄)^–
B₂H₆ + 2NaH → 2Na⁺(BH₄)^–

Question 9.
Describe ortho and para hydrogen. How will you obtain para hydrogen?
Answer:
Hydrogen atom consists of one proton in the nucleus and one electron in the extra nuclear part. Both electron and nucleus spin about their own axis. (MPBoardSolutions.com) When two atoms of hydrogen combine to form a hydrogen molecule, the spins of electron should be in opposite direction but the spins of nuclei may either be in the same direction or in opposite directions. When nuclear spins are in same direction, it is called ortho hydrogen. When nuclear spins are in opposite directions, it is called para hydrogen.

Preparation of para hydrogen:
Para hydrogen can be obtained from ordinary hydrogen by keeping it in a quartz vessel with active charcoal at 20K for about 3 to 4 hours.

Question 10.
Why, hard water does not used in boiler?
Answer:
1. Hard water is not used in boiler because compound of calcium and magnesium are deposited on internal side of boiler. This coating is bad conductor of heat so wastes of fuel take place. Due to this coating boiler have to the heated very much for heating water.

2. The boiler may burst if sudden cracks appear in boiler scale. Due to these sudden cracks, the water that comes in contact with the heated boiler is at once converted into steam and the sudden increase in pressure may cause the boiler to burst.

3. Hydrogen is volatile gas therefore, it is risk for explosion.

Question 11.
How the production of dihydrogen obtained from coal gasification can be increased?
Answer:
The gasification of producing syn gas from coal or coke is called coal gasification.

This is called water gas shift reaction. The CO₂ thus produced is removed by scrub-bing with sodium arsenite solution.

Question 12.
Expiain the structure of hydrogen peroxide?
Answer:
Dipole moment of H₂O₂ is 2.1 D, it indicates that structure of H₂O₂ is non – planar. By X – rays and other physical methods it is known that structure of H₂O₂ is like open book. (MPBoardSolutions.com) In gaseous state planes form an angle of 111.5°. In the axis, there are two oxygen atoms and one hydrogen in each plane.

The H – O and O – O bond lengths are 0.95Å and 147Å respectively. There is a slight change in the crystalline state due to hydrogen bonding. The angle between the planes is 90.2°, angle O – O – H = 101.9°, bond length H – O = 0.99Å and O – O is 1.46Å.

According to modem and latest belief probably both forms occur in equilibrium in aqueous solutions involving ionisation which explains the feeble acidic nature of hydrogen peroxide.

Question 13.
What is water gas? Write its constituents and uses?
Answer:
Bosch processes:
When steam is passed over red hot coke, water gas is produced.

Water gas is mixed with steam and passed over Fe₂O₃ oxidized to CO₂.

This mixture of CO₂ and H₂ is passed in water at 25 atmospheric pressure CO₂ gas is absorbed and H₂ gas remains.
Constitution:
H₂ = 49%, N₂ = 4%, CO = 44%, CO₂ = 2.7%, CH₄ = 0.3%
Uses:

1. As fuel in furnaces
2. For preparation of carbonated water gas
3. For manufacturing of ammonia.

Question 14.
What do you understand by the term “non – stoichiometric” hydrides? Do you expect this type of the hydrides to be formed by alkali metals? Justify your answer?
Answer:
The hydrides in which the ratio of the metal and hydrogen is found to be fractional are called non – stoichiometric hydrides. It is also observed that this fractional ratio is not fixed but varies with the temperature and pressure. (MPBoardSolutions.com) Such hydrides are formed by d and f – block elements. Usually all the holes are not occupied i.e., some holes always remain vacant and thus, these compounds are non – stoichiometric. Alkali metals do not form non – stoichiometric hydrides as each sodium atom loses its valency electron which is accepted by hydrogen atom to form H^– ion. In this way, an ionic compound, Na⁺ H^–, is formed.

Question 15.
What is Calgon? How hardness of water is removed by using it?
Answer:
Calgon is a trade name for the complex salt (NaPO₃)6 as Na₂ [Na₄ (PO₃)₆]. When calgon is added to hard water are rendered ineffective due to the formation of water soluble complex ion. This is known as sequstration.
Na₂[Na₄(PO₃)₆] + 2CaCl₂ → Na₂[Ca₂(PO₃)₆] + 4NaCl
Na₂ [Na₄(PO₃)₆] + 2MgSO₄ → Na₂[Mg₂ (PO₃)₆] + 2Na₂SO₄
The complex calcium and magnesium ion do not form any precipitate with soap. Therefore, they readily form lather with soap solution. Modem detergent contains sodium hexa – meta phosphate to remove the hardness of water due to Ca²⁺ and Mg²⁺ ion hence wastage of soap is checked.

Question 16.
Explain that H₂O₂ acts as both oxidizing and reducing agent. Why?
Answer:
H₂O₂ liberates oxygen atom easily, so it is strong oxidizing agent, but when it reacts with other oxidizing agent, it easily extracts oxygen atom from them hence, it possesses reducing property too.
Oxidizing nature:
1. 2KI + H₂O₂ → 2KOH + I₂

Reducing nature:
(a) In basic medium, it converts ferricyanide to ferrocyanide.
2[Fe(CN₆)]^3- + 20H^– + H₂O₂ → 2[Fe(CN)₆]^4- + 2H₂O + O₂

(b) In acidic medium; it reduces permanganate to manganese (II) salt.
2MnO₄^– + 6H⁺ + 5H₂O₂ → Mn²⁺ + 8H₂O + 5O₂

Question 17.
Consider a reaction of water with F₂ and suggest, in terms of oxidauon and reduction, which species will oxidized/reduced?
Answer:
2F_2(g) + 2H₂O_(l) → O_2(g) + 4H⁺_(aq) + 4F^–_(aq)
3F_2(g) + 3H₂O_(l) → O_2(g) + 6H⁺_(aq) + 6F^–_(aq)
In these reactions, water acts as a reducing agent as it gets oxidized to either O₂ or O₃ while fluorine acts as an oxidizing agent as it is reduced to F^– ion.

Question 18.
How does H₂O₂ behave as bleaching agent?
Answer:
Hydrogen peroxide acts as a bleaching agent due to the release of nascent oxygen.
H₂O₂ → H₂O + [0]
The nascent oxygen combines with colouring matter which in turn gets oxidized. The bleaching action of H₂O₂ is due to the oxidation of colouring matter by nascent oxygen. It is used for bleaching materials like jury, silk, wool, feathers etc.

Question 19.
Why the density of water is maximum at 4°C?
Answer:
Maximum density of water:
Melting of ice decreases hydrogen bonds because cage – like structure is broken. With increase in temperature from 0°C to 4°C with the cleavage of H – bonds, water molecules starts moving closer to each other as a result volume decreases while density increases. (MPBoardSolutions.com) When the temperature becomes greater than 4°C, kinetic energy of H₂O molecule increases resulting in expansion of water. As a result of this volume increases while density decreases. That is at 4°C, density of water is maximum.

Question 20.
What do you understand by

1. Electron deficient
2. Electron precise and
3. Electron rich compounds of hydrogen? Provide justification with suitable examples?

Answer:
1. Electron deficient hydride:
Electron deficient hydrides are those which do not have sufficient number of electrons to form normal covalent bond.
Examples: BH₃, AlH₃
To makeup their deficiency they generally exist in polymeric form such as B₂H₆, Al₂H₆.

2. Electron precise hydride:
Electron precise hydrides are those which have suffi-cient number of electrons required for forming covalent bond.
Examples:
CH₄, SiH₄ etc.

3. Electron rich hydride:
Electron rich hydrides are those which have excesses electron as required to form normal covalent bond. The excesses electron present as lone pair.
Examples: NH₃, PH₃ etc.

Question 21.
Tell the group of hydrides which include H₂O, B₂H₆ and NaH?
Answer:

• H₂O: Covalent or molecular hydride (Electron rich hydride)
• B₂H₆: Covalent or molecular hydride (Electron deficient hydride)
• NaH: Ionic or salt hydride.

Hydrogen Long Answer Type Questions

Question 1.
Explain Permutit process of removal of hardness of water?
Answer:
Permutit process or Zeolite process:
The water is passed over such substances which readily replace the Ca²⁺ and Mg²⁺ ions of hard water by sodium ions. The water does not become hard in presence of sodium salts. Ofcourse too much of sodium salts also make it hard just as in sea water. (MPBoardSolutions.com) The water thus obtained is soft. These products are called as zeolites. Zeolite is a technical name given to certain hydrated silicates of aluminium and sodium. It is also known as permutit. It is obtained by fusing sodium carbonate with alumina and silica.

Na₂CO₃ + Al₂O₃ + 2SiO₂ → Na₂Al₂Si₂O₈ + CO₂
Na₂Al₂Si₂O₈ is known as sodium zeolite and Al₂Si₂O₈ is zeolite and can be represented by Z. Sodium zeolite reacts with chlorides, sulphates of Ca and Mg as given below and hardness is removed.
CaCl₂ + Na₂ → CaZ + 2NaCl
MgSO₄ + Na₂ → MgZ + Na₂SO₂
Reactions have been given by representing sodium zeolite as Na₂Z.
After sufficient use permutit gets exhausted and cannot be used further. It is regenerated and made usable by passing 10% solution of sodium chloride.
CaZ + 2NaCl → CaCl₂ + Na₂Z
MgZ + 2NaCl → MgCl₂ + Na₂Z

Question 2.
What happens when:

1. Calcium hydride reacts with water
2. H₂O₂ is added in acidic KMnO₄ solution
3. Reaction of potassium ferricyanide with H202
4. Reaction of H₂ with N₂ at high temperature and pressure in presence of Fe?

Answer:

1. On reaction of calcium hydride with water, H₂ is formed
   CaH₂ + 2H₂O → Ca(OH)₂ + 2H₂
2. The pink colour disappear of KMnO₄
   2KMnO₄ + 3H₂SO₄ + 5H₂O₂ → K₂SO₄ + 2MnSO₄ + 8H₂O + 5O₂
3. On adding H₂O₂ in potassium ferricyanide, it reduces to potassium ferrocyanide
   2K₃[Fe(CN)₆] + 2KOH + H₂O₂ → 2K₄[Fe(CN)₆] + 2H₂O + O₂
4. Ammonia is formed when hydrogen reacts with N₂ 200 atm. pressure

Question 3.
Explain the processes of formation of hydrogen in laboratory?
Answer:
Preparation of hydrogen (laboratory method):
Hydrogen is prepared in laboratory by action of dil. H₂SO₄ on granulated Zn. Zn is taken into woulf bottle fitted with thistle funnel and a outlet tube.
Hydrogen formed by this method is collected over water by displacement method.
Zn + H₂SO₄ → ZnSO₄ + H₂↑
Purification of hydrogen : Hydrogen prepared by this method contains following impurities:

1. Arsine (AsH₃) and phosphene (PH₃)
2. H₂S
3. SO₂, CO₂ and oxides of nitrogen (NO₂)
4. Water vapours.

In order to remove these impurities, gas is passed in a series of U – tubes containing different solutions:

1. Passed in tube filled with AgNO₃ solution to absorb AsH₃ and PH₃.
2. Passed in the tube containing lead nitrate solution to remove H₂S.
3. Passed in the tube filled with cone. KOH solution to remove SO₂, CO₂ and NO₂.

Question 4.
Rohan heard that instructions were given to the laboratory attendent to store a particular chemical Le., keep it in the dark room, add some urea in it, and keep it away from dust This chemical acts as an oxidizing as well as a reducing agent in both acidic and alkaline media. This chemical is important for use in the pollution control treatment of domestic and industrial effluents?

1. Write the name of this compound.
2. Explain, why such precautions are taken for storing this chemical?

Answer:

1. H₂O₂ (Hydrogen peroxide).
2. The following precautions must be taken while storing hydrogen peroxide:
3. It must be kept in wax lined coloured bottles because the rough glass surface, light and dust particles are responsible for its decomposition.
4. A small amount of negative catalyst such as urea, glycerol, phosphoric acid etc. is generally added which retards its decomposition.

Question 5.
Calculate the strength of 5 volume of H₂O₂ solution?
Answer:
5 volumes ₂O₂ solution means that 1 volume of this solution will decompose to give 5 volumes of oxygen at S.T.P.

5 L oxygen is obtained from \(\frac{68×5}{22.4}\) g H₂O₂ = 15.17 g H₂O₂
i.e. 15g H₂O₂ is present in 1L solution. Thus, strength of the solution = 15 g/L.

Question 6.
Complete the following reactions:

1. PbS_(s) + H₂O_2(aq) →
2. MnO₄^–_(aq) + H₂O_2(aq) →
3. CaO_(s) + H₂O_(g) →
4. AlCl_3(g) + HzO_(l) →
5. Ca₃N_2(s) + H₂O_(l) →

above

1. Hydrolysis
2. Redox
3. Solvation process.

Answer:

MP Board Class 11 Chemistry Important Questions

MP Board Class 11th Chemistry Important Questions Chapter 8 Redox Reactions

Redox Reactions Important Questions

Redox Reactions Objective Type Questions

Question 1.
Choose the correct answer:

Question 1.
Metals used in Daniel cell are:
(a) N and Cu
(b) Zn and Ag
(c) Ag and Cu
(d) Zn and Cu
Answer:
(d) Zn and Cu

Question 2.
Which of the following is strongly reducing:
(a) r
(b) cr
(c) Bf
(d) r
Answer:
(d) r

Question 3.
Oxidation in electrolyte occurs:
(a) At anode
(b) At cathode
(c) At both the electrodes
(d) None of these
Answer:
(a) At anode

Question 4.
Which of the following statement is correct? Galvanic cell converts:
(a) Chemical energy to electrical energy
(b) Electrical energy to chemical energy
(c) Electrical state of metal to combined state
(d) Electrolytes to ions
Answer:
(b) Electrical energy to chemical energy

Question 5.
Oxidation number of chlorine in HOCl is:
(a) – 1
(b) 0
(c) +I
(d) +2
Answer:
(c) +I

Question 6.
Oxidation number of Mn in K₂MnO₄ is:
(a) +2
(b) +6
(c) +7
(d) 0
Answer:
(b) +6

Question 7.
Oxidation number of Cr in K₂Cr₂O₇ is:
(a) -6
(b) +6
(c) +2
(d) -2.
Answer:
(b) +6

Question 8.
Oxidation number of Ni in Ni(CO)₄ is:
(a) 0
(b) +2
(c) +1
(d) – 1.
Answer:
(a) 0

Question 9.
Unit of cell constant is:
(a) ohm^-1cm^-1
(b) ohm cm
(c) cm
(d) cm^-1
Answer:
(d) cm^-1

Question 10.
Oxidation state of nitrogen is maximum in:
(a) N₃H
(b) NH₂OH
(c) N₂H₄
(d) NH₃
Answer:
(a) N₃H

Question 11.
Oxidation state of oxygen is zero in:
(a) CO
(b) O₃
(c) SO₂
(d) H₂O₂
Answer:
(b) O₃

Question 12.
Oxidation state of Fe in K₄[Fe(CN)₆] is:
(a) +2
(b) +6
(c) +3
(d) +4
Answer:
(a) +2

Question 13.
Oxidation state of S In H₂S₂O₈ is:
(a) +2
(b) +4
(c) +6
(d) +7
Answer:
(c) +6

Question 14.
Oxidation state of Mn in KMnO₄ is:
(a) +4
(b) +6
(c) +7
(d) +5
Answer:
(c) +7

Question 15.
oxidation state of chlorine is in:
(a) HCl
(b) HClO₄
(c) ICI
(d) Cl₂O
Answer:
(d) Cl₂O

Question 16.
Oxidation state of Cl in ClO₃^– ion is:
(a) +4
(b) +5
(c) +3
(d) +2
Answer:
(b) +5

Question 17.
Halogen which is reduced most easily is:
(a) I₂
(b) Br₂
(c) Cl₂
(d) F₂
Answer:
(a) I₂

Question 18.
Oxidation state of C in CCl₄ is:
(a) +4
(b) -4
(c) +6
(d) – 6
Answer:
(a) +4

Question 19.
Oxidation state of S in S0₄^-2 is:
(a) +6
(b) -6
(c) +5
(d) – 5
Answer:
(a) +6

Question 20.
Oxidizing agent are:
(a) Electron acceptor
(b) Electron donor
(c) Proton acceptor
(d) Neutron acceptor
Answer:
(a) Electron acceptor

Question 2.
Fill in the blanks:

1. Process of loss of electrons is called ……………………..
2. Process of gain of electrons is called …………………….
3. The deterioration of metals in presence of atmospheric gases and moisture is called …………………………
4. A device in which electric energy gets converted to chemical energy is called …………………….. cell
5. In electrochemical series the ability to reduce ………………………… on moving down
6. Most strong reducing element is ………………………….
7. Most strong oxidizing element is ………………………..
8. Theory of dissociation of electrolyte was proposed by ……………………….

Answer:

1. Oxidation
2. Reduction
3. Corrosion
4. Electrochemical cell
5. Decreases
6. Lithium
7. Fluorine
8. Arrhenius

Question 3.
Answer in one word/sentence:

1. What is balanced redox reaction?
2. Why does iron displaced copper from its salt solution?
3. What is the oxidation state of chlorine in Cl₂O?
4. Why does an electrolyte dissociate into ions when dissolved in water?
5. A saturated solution of KNO₃ is used for the formation of salt bridge. Why?
6. In SnCl₂ + 2 FeCl₃ → SnCl₄ + 2 FeCl₂, reaction which element is oxidizing agent?
7. What is oxidation state of Xe in XeO₃?

Answer:

1. Redox reaction in which amount of oxidation and reduction is to the same extent.
2. Because standard eletrode potential value of iron is less then the standard electrode potential of copper.
3. +1
4. Because the electrostate attractive force between the ions break due to water.
5. Because the speed of K⁺ and NO₃ and is almost same.
6. FeCl₃
7. +6

Question 4.
Match the following:

Answer:

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

Redox Reactions Very Short Answer Type Questions

Question 1.
Why iron displaces copper from its salt solution?
Answer:
Because the standard electrode potential of iron is less than copper.

Question 2.
What is the oxidation number of Cl in Cl₂O?
Answer:
+1.

Question 3.
When an electrolyte is dissolved in water, it dissociates into ions? Why?
Answer:
Because due to water the electrostatic attraction force between the ions breaks.

Question 4.
Why the saturated solution of KNO₃ is used to prepare salt bridge?
Answer:
Because the speed of K⁺ and NO₃^– ions is similar.

Question 5.
In SnCl₂ + 2FeCl₃ → SnCl₄ + 2FeCl₂, which is oxidizing agent?
Answer:
FeCl₃.

Question 6.
What is the oxidation number of Xe in XeO₃?
Answer:
+6.

Question 7.
Which metal is used in Daniel cell?
Answer:
Lithium.

Question 8.
What is the oxidation state of Mn in K₂MnO₄?
Answer:
+6.

Question 9.
Which is the most reducing element?
Answer:
Lithium.

Question 10.
Who maintains the neutrality among the two half cells?
Answer:
Salt bridge.

Question 11.
What is the standard electrode potential of SHE?
Answer:
0.00V (Zero).

Question 12.
Which is the best conducting metal?
Answer:
Silver (Ag).

Question 13.
The reaction 3ClO^–_aq → Cl₃^– + 2Cl^– is an example of?
Answer:
Disproportionation reaction.

Question 14.
Which halogen reduces very easily?
Answer:
F₂.

Question 15.
Which reaction is called electron acceptance reaction?
Answer:
Reduction.

Question 16.
Where oxidation occurs in electrolysis?
Answer:
At anode.

Redox Reactions Short Answer Type Questions – I

Question 1.
What is oxidation process? Explain redox reaction with example?
Answer:
Oxidation state of an element is defined as “The residual charge left on its atom”. When all the other atoms are removed from the molecule as ion.

2Mg + O₂ → 2MgO [Addition of oxygen]
2FeCl₂ → 2FeCl₃ [Addition of electronegativity element]
H₂S + Cl₂ → S + 2HCl [Removal of hydrogen]
2Ki + H₂O₂ → 2KOH + I₂ [Removal of electropositive element]

Question 2.
What is reduction process? Explain with example?
Answer:
The ability of any substance to accept hydrogen atom or +ve electrolytic element or to release oxygen or – ve element is called reduction process.
CuO + H₂ → Cu + H₂O [Remove of oxygen]
2FeCl₃ + H₂ S → 2FeCl₂ + 2HCl + S [Removal of electromagnetive element]
Cl₂ + H₂S → 2 HCl + S [Addition of H]
S + Fe → Fes [Addition of electropositive element]

Question 3.
AgF₂ is unstable compound, but if it is formed then it will acts as strong oxidising agent Why?
Answer:
In AgF₂, Ag has oxidation state +2, it is highly unstable, it very easily accept electron and forms oxidation state +1. Because Ag⁺ has stable configuration so it is stable.
Ag2⁺ + e^– → Ag⁺
This is the reason why AgF₂ behaves as a strong oxidizing agent.

Question 4.
By the structure of S₄O₆^2-clarify that the oxidation state of S is +5?
Answer:
The oxidation state of two central sulphur atom is 0. As the electron pair remains in the centre cf the bond. So the remaining sulphur atom has oxidation state 4 – 5.

⇒ 6(-2) + 2x = -2
⇒ -12 + 2x = -2
⇒ 2x = -2 + 12 = 10
⇒ x = \(\frac{10}{2}\) = 5.

Question 5.
What is electrochemical series?
Answer:
Electrochemical series:
When different elements and ions are arranged in increasing order of their standard electrode potential, a series is obtained which is called electrochemical series as activity series.

Question 6.
What is salt bridge? Write its two uses?
Answer:
1. It connects the solution in two half ceil and completes the cell circuit

2. The salt bridge which contains the solution of an electrolyte say K⁺NO₃^– maintains the electrical neutrality by diffusion of ion through it. As positive ion begins to be formed in oxidation half cell negative ion from the salt bridge diffuse out into this half cell. Similarly, as the positive Ion begin to be consumed in the reduction.

Hair cell positive:
On from the salt bridge diffuse out into this half cell. As a result the solution in the two half cell remain electrically neutral and the current continous to flow.

Question 7.
On the basis of electron transfer explain oxidation and reduction reactions?
Answer:
Reactions involving exchange of electrons are called redox reaction. Reaction given below
2FeCl₃ + SnCl₂ → 2FeCl₂ + SnCl₄
It is an example of redox reaction in which FeCl₃ is oxidizing agent while SnCl₂ is a reducing agent.

According to electronic concept during oxidation substance loses one or more electron and its positive oxidation number increases while negative oxidation number decreases. (MPBoardSolutions.com) On the other hand, during reduction substance gains one or more electron and is positive oxidation number decreases while negative oxidation number increases.

Question 8.
What is electrochemical equivalent?
Answer:
According to Faraday’s first law:
The mass of any substance deposited at any electrode is directly proportional to the quantity of electricity passed.

Thus, if W gm substance is deposited on passing Q coulomb 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 × t. (MPBoardSolutions.com) So that, W = Z × Q = Z × I × r

Thus, if, Q = 1 coulomb, 1=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, electrochemical equivalent can be calculated from the equivalent mass.
\(\frac { Equivalentmassofthesubstance\quad }{ 96500 } \)

Question 9.
What happens when Zn is kept in CuS0₄ solution? Explain with equation?
Answer:
The reaction occurring in the beaker may be written as

Cancelling the common S0₄²⁺ ions
Zn_(s) + Cu²⁺_(eq) → Zn²⁺_(eq) + Cu_(s)
In this case Zinc metal loses electron and gets oxidised to Zn⁺⁺ ions which goes into the solution. Due to this, weight of zinc plate gradually decreases. On the other hand, electrons lost by Zinc atom are taken up by Cu²⁺ ions of CuS0₄ solution.

Question 10.
What do you mean by standard electrode potential?
Answer:
Standard electrode potential: Standard electrode potential (E°) of a half cell (electrode) is the potential difference which is produced when one electrode is dipped in the solution of molar concentration of its ion at 298 K. (MPBoardSolutions.com) If electrode is gaseous, the pressure of gas must be one atmosphere.
In IUPAC system reduction potentials are known as standard electrode potential.

Question 11.
The reaction Cl_2(g) + 2OH^–_(aq) → ClO^–_(aq) + Cl^–_(aq) + H₂O_(l) represents the process of bleaching. Identify and name species that bleaches the substances due to its oxidizing action?
Answer:

In this reaction, O. N. of Cl increases from 0 in Cl₂ to +1 in ClO^– and decreases to -1 in Cl^–. Therefore, Cl₂ is both oxidized to ClO^– and reduced to Cl^– (Disproportionation reaction). Since, Cl^– ion cannot act as oxidizing agent (Because it cannot decrease its O.N. lower than -1) therefore, Cl₂ bleaches substance due to oxidizing action of ClO^– (Hypochlorite) ion.

Question 12.
Define oxidizing agent and reducing agent?
Answer:
Oxidizing agent:
A substance which brings oxidation is called oxidising agent. On the basis of electronic theory, an oxidizing agent may be defined as an electron acceptor. i.e. (MPBoardSolutions.com) in the reaction between Zn atom and Cu²⁺ ion in aqueous solution of Cu²⁺ salt, Cu²⁺ ion is the oxidizing agent as it brings about the oxidation of Zn atom by gaining the electron lost by it.
Zn + Cu²⁺ → Zn² + Cu
(Gains e^–)
(∴ Oxidising agent)
Thus, oxidizing agent or oxidant undergoes gain of electrons during the reaction.
Reducing agent:
A substance which brings about reduction is called a reducing agent. On the basis of electronic theory, a reducing agent may be defined as an electron donor, e.g., in reaction between Zn atom (MPBoardSolutions.com) Cu²⁺ ion in an aqueous salt solution of Cu²⁺, Zn atom is the reducing agent as it brings about reduction of Cu²⁺ ion by losing the electrons.
Zn + Cu²⁺ → Zn²⁺ + Cu
(Loses e^–)
(∴Reducing agent)

Question 13.
If iron rod is dipped in CuS0₄ solution then copper is displaced from its solution by iron but when copper rod is dipped in FeS04 solution. Why iron is not displaced by copper? Explain?
Answer:
Fe occupies higher position in electrochemical series than Cu. So, Fe is more active than Cu. That is why Fe displaces Cu from CuS0₄ solution, but Cu is not able to displace Fe from FeS0₄ solution.

Question 14.
What is oxidation number?
Answer:
Oxidation number of an element is defined as, “The residual charge left on its atom when all the other atoms are removed from the molecule as ions.” Atoms can have positive, negative or zero oxidation state depending upon their state of combination. (MPBoardSolutions.com) In fact, oxidation number is the charge assigned to the atom in a species according to some rules. It is also known as oxidation state.

Question 15.
In electrochemical series, the activity of metals increases or decreases in which sequence?
Answer:
Species present in the right of electrochemical series are reducing agent. Smaller the value of E°, stronger is the reducing agent. The activity of metals decrease on going down the electrochemical series.

Question 16.
What is E° value be + ve shows in Galvanic cell?
Answer:
The positive value of E° shows:

1. Oxidation occurs at anode and
2. The electrode where reduction occurs can be taken as cathode.

Question 17.
What is electrode potential? Its value depends on what factors?
Answer:
The electrical potential difference setup between the metal and its solution is known as electrode potential.
The electrode potential depends upon:

1. Concentration of ions in the solution
2. Temperature.

Question 18.
On the basis of standard electrode potential given below, arrange the metals in their increasing reducing power?
K⁺/ K = – 2.93V, Ag⁺/ Ag = 0.80V, Hg²⁺/ Hg = 0.79V, Mg²⁺/ Mg = -2.37V, Cr³⁺/ Cr = -0.74V?
Answer:
Less the value of E°, the reducing power increases of the metal. So the sequence is Ag < Hg < Cr < Mg < K.

Question 19.
Among MgO, ZnO, CuO and CaO which oxide will reduce by hydrogen?
Answer:
Mg, Zn and Ca are more reactive than H in electrochemical series. So they will not reduced by H. Cu is present below H, so the reactivity of Cu is less than H. So CuO will easily get reduced by H.

Question 20.
The electrode potential (E°) of Ag, Ba, Mg and Au are +0.80, -2.90, -2.37 and +1.42 volt. Among these metals which will displace H from acids and which will not?
Answer:
Those metals which have E° value negative they are more reactive than hydrogen and can easily displace H from weak acids. So, Ba and Mg can displace H from acid solution.

Question 21.
Can be put CuSO₄ solution in silver container? Why?
Answer:
In electrochemical series Ag comes below Cu, so reactivity of Ag is less than Cu. There Ag will not displace Cu from CuSO₄ solution. CuSO₄ can be kept in Ag container.

Redox Reactions Short Answer Type Questions – II

Question 1.
Fluorine reacts with ice as follows:
H₂O_(s) → HF_(g) + HOF_(g)
Justify that, this reaction is a redox reaction.
Answer:

Since, fluorine can undergo oxidation as well as reduction, it is an example of redox reaction.

Question 2.
In acidic medium MnO₄^2- shows disproportionation reaction but MnO₄^– does not show why?
Answer:
In oxidation state of Mn in MnO₄^-2 is +6. It can increase oxidation state (+7) and decrease (+4, +3, +2, 0 etc.). So in acidic medium it shows disproportionation reaction.

In MnO₄^–, Mn has maximum oxidation state (+7). It can only decrease its oxidation state. Due to which it cannot show disproportionation reaction.

Question 3.
In the following reaction whose oxidation and whose reduction occur:
PbS + 4H₂O₂ → PbSO₄ + 4H₂O
Answer:
In this reaction PbS is oxidized as PbSO₄ and H₂O₂ is reduced to form H₂O.

Question 4.
Differentiate between oxidation number and valency?
Answer:
Differences between Oxidation number and Valency:
Oxidation:

1. It is the residual charge left on the atom of an element when all other atoms are removed from molecule or ion.
2. It refers to charge and can be positive, negative or zero, e.g., oxidation number of C in CO₂ is +4 and that of oxygen is -2.
3. It may have fractional value.
4. Elements like C, N, O have variable oxidation number.

Valency:

1. It is the combining capacity of the element expressed as number of H – atom or double the number of oxygen atoms which combine with one atom of the element.
2. It refers to number only and does not carry any sign, e.g., in CO₂ valency of carbon is 4 and that of oxygen is 2.
3. It is always a whole number.
4. Elements like C, N, O exhibit constant valency.

Question 5.
Why fluorine doesn’t show disproportionation reaction?
Answer:
Like chlorine, bromine and iodine also undergo similar disproportionation reactions but fluorine does not. The reason for this anomalous behaviour is that fluorine being the strongest oxidizing agent does not show positive oxidation states. It, therefore, reacts in a different way forming oxygen difluoride (OF2).
2F_2(g) + 2OH^–_(g) → 2F^–_(aq) + OF_2(g) + H₂O_(l)

Question 6.
Show that galvanic cell where following reaction occurs:
Zn_(s) + 2Ag⁺_(aq) → Zn²⁺_(aq) + 2 Ag_(s)
Now explain :

1. Which electrode is -ve?
2. What is the motive of electricity in cell?
3. What is the reaction occurring on each electrode?

Answer:
Galvanic cell Zn_{(s) ∥} Zn²⁺_(aq)Ag(aq) ∥ Ag⁺_(aq) ∥ Ag_(s)

1. Zn electrode is negatively charged. Zn is oxidized into Zn⁺².
2. Electricity flows from Ag electrode to Zn electrode and electrons flow from Zn to Ag electrode.
3. Reactions on electrode:

Cathode — Zn_(s) → Zn⁺²_(s) + 2e^–
Anode — 2Ag⁺_(aq) + 2e^– → 2Ag_(s)

Question 7.
Write the definition of electrochemical cell? Write the chemical reactions of Daniel cell?
Answer:
An electrochemical cell (Galvanic cell) is a device in which the redox reaction takes place indirectly and the decrease in free energy appears in the form of electrical work i.e. chemical energy is converted into electrical energy.

Question 8.
Write the factors affecting electrode potential?
Answer:
The factors affecting electrode potential are:

1. Tendency of metal to donate electrons: More the tendency to release electron more will be electrode potential.
2. Temperature: With increasing temperature electrode potential increases.
3. Concentration of solution: More the concentration of solution more will be electrode potential.

Question 9.
Determine the oxidation number of following:

1. Cr in K₂Cr₂O₇
2. Mn in KMnO₄
3. S in Na₂S₄O₆.

Solution:
1. Cr in K₂Cr₂O₇
2 (+1) + 2x + 7 (-2) = 0
or 2 + 2x – 14 = 0
or 2x = 12
or x = +6.

2. Mn in KMnO₄
1 (+1) + 1x + 4(-2) = 0
or 1 + x – 8 = 0
or x = +7.

3. S in Na₂S₄O₆
2 (+1) + 4x + 6 (-2) = 0
or 2 + 4x – 12 = 0
or 4x = 10
or x = 2.5.

Question 10.
Why does the following reactions occur:
XeO_6(aq)^4- + 2F^–_(aq) + 6H⁺_(aq) → XeO_3(g) + F_2(g) + 3H₂O_(l)?
What conclusion about the compound Na₄XeO₆ (of which XeO₆^4- is a part) K₂MnF₆ can be drawn from the reaction?
Answer:

O.N. of Xe decreases from +8 to +6. This shows that XeO₆^4- is an oxidizing agent. It oxidises F^– to F₂. This reaction shows that Na₂XeO₆ (or XeO₆^–) is a stronger oxidizing agent than F₂.

Question 11.
Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess chlorine is removed by treating with sulphur dioxide. Present a balanced equation for this redox change taking place in water?
Answer:

Multiplying Cl^– by 2 (As 2 atoms are in Cl₂)
Cl_2(aq) + SO_2(aq) + H₂O_(l) → 2Cl^–_(aq) + SO₄^2-_(aq)
On adding 4H⁺ in left side and multiplying in H₂O by 2,
Cl_2(aq) + SO_2(aq) + 2H₂O_(l) → 2Cl^–_(aq) + SO₄^2- + 4H⁺
It is a balanced disproportionation reaction.

Question 12.
Differentiate between electrochemical cell and electrolytic cell?
Answer:
Differences between electrochemical cell and electrolytic cell:
Electrochemical (Galvanic) cell:

1. In Galvanic cell, chemical energy is changed into electrical energy.
2. Reaction in Galvanic cell is spontaneous.
3. Oxidation and reduction occurs in different half cell.
4. Anode is negative while cathode is positive terminal.
5. The electrons move from anode to cathode in the external circuit.

Electrolytic cell:

1. In electrolytic cell, electrical energy is changed into chemical energy.
2. Reaction in electrolytic cell is non – spontaneous.
3. Oxidation and reduction occurs in same container.
4. Anode is positive while cathode is negative terminal.
5. The electrons are supplied by the external circuit which enter through the cathode and came out through anode.

Question 13.
What is Nernst equation? Derive relation between E and E°?
Answer:
In Standard cell, the concentration of the solution used is 1M and the temperature is maintained at 25°C (For 298K). But the Galvanic cells are often constructed under non standard condition. In such cases the cell voltage (or EMF) is calculated by Nernst equation as follows:
E = E° – \(\frac{RT}{nF}\) log_e \(\frac { M_{ (s) } }{ M^{ n+ }_{ (aq) } } \)
or E = E° + \(\frac{RT}{nF}\) log_e \(\frac { M^{ n+ }_{ (aq) } }{ M_{ (s) } } \)
In changing log_e in log₁₀
or E = E° + \(\frac{2.303}{nF}\) log₁₀ \(\frac { M^{ n+ }_{ (aq) } }{ M_{ (s) } } \) [M_(s) = 1]
or E = E° + \(\frac{2.303RT}{nF}\) log₁₀[Mⁿ⁺_(aq)]
or E = E° + \(\frac{0.0591}{nF}\) log₁₀ [Mⁿ⁺_(aq)].

Question 14.
Consider the reactions:
2S₂O₃^2-_(aq) + I_2(s) → S₄O₆^2-_(aq) + 2I^–_(aq)
S₂O₃^2-_(aq) → 2SO₄^2-_(aq) + 4Br^–_(aq) + 10H⁺_(aq)
Why does the same reductant, thiosulphate reacts differently with iodine and bromine?
Answer:
Br₂ is stronger oxidizing agent than I₂, it oxidises SO₃^2- to SO₄^2- i. e. from +2 state to +6 state of sulphur. However, I₂ being weaker oxidizing agent, oxidises S₂O₃^2- to S₄O₆^2- ion i.e. from + 2 to + 2.5 state of sulphur.

Redox Reactions Long Answer Type Questions – I

Question 1.
What is standard hydrogen electrode? How it is 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 atmospheric increase its surface. (MPBoardSolutions.com) The hydrogen electrode thus Pressure 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 1 M H+solution circumstances works both as anode or cathode.

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

Question 2.
On the basis of electrode potential explain which reaction is feasible:
E°_Cu2+/Cu = 0.34 V, E°_Zn2+/Zn = -0.76 V, E°_Mg2+/Mg = 2.37 V, E°_Fe2+/Fe = -0.74V

1. Cu + Zn²⁺ → Cu²⁺ + Zn
2. Mg + Fe²⁺ → Mg²⁺ + Fe.

Solution:
1. Cu + Zn²⁺ → Cu²⁺ + Zn
E°_Cu²⁺/Cu = 0.34 V and E°_Zn2+/Zn = – 0.76 V
In given cell, Cu oxidised to Cu²⁺. So Cu²⁺/Cu will act as anode and Zn²⁺/Zn acts as cathode.
E°_cell = E°_cathode – E°_anode
E°_cell = – 0.74 – (-2.37) = +1.63V
E°_cell = +Ve, shows that the reaction is feasible.

2. Mg + Fe²⁺ → Mg²⁺ + Fe
E°_Mg²⁺_/Mg = 2.37 V and E°_Cu²⁺/Cu = – 0.74 V
Mg oxidised to Mg²⁺ and acts as anode Mg²⁺/Mg.
Fe²⁺ reduced to Fe and acts as cathode Fe²⁺/Fe.
E°_cell = E°_cathode – E°_anode
E°_cell = – 0.74 – (-2.37) = +1.63 V

Question 3.
While sulphur dioxide and hydrogen peroxide can act as oxidizing as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants, why?
Answer:
In sulphur dioxide (SO₂) and hydrogen peroxide (H₂O₂), the oxidation states of sulphur and oxygen are +4 and -1 respectively. Since, they can increase as well as decrease when there compounds take part in chemical reaction, they can act as oxidizing as well as reducing agents. For example,
Increase in O.N.

In ozone (O₃), the oxidation state of oxygen is zero while in nitric acid (HNO₃), the oxidation state of nitrogen is +5. Since, both of them can undergo decrease in oxidation state and not an increase in its value, they can act only as oxidizing agents and not as reducing agents.

In ozone (O₃), the oxidation state of oxygen is zero while in nitric acid (HNO₃), the oxidation state of nitrogen is + 5. Since both them can undergo decrease in oxidation state and not an increase in its value, they can act only as oxidizing agents and not as reducing agents.

Question 4.
How do you count for the following observation though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants, yet in manufacture of benzoic acid from toluene we use alcoholic potassium permanganate as an oxidant, why? Write a balanced redox equation for the reaction?
Answer:
Toluene can be oxidized to benzoic acid in acidic, alkaline and neutral medium by using potassium permanganate.

1. In acidic medium:
[MnO^–_4(aq) + 8H⁺_(aq) + 5e^– → Mn²⁺_(aq) + 4H₂O_(l)] × 6

In the manufacture of benzoic acid alcoholic KMnO₄ is more useful.
Alcohol if used as solvent will help in the formation of a homogeneous mixture between toluene (non – polar) and KMnO₄ (ionic). Actually alcohol has non – polar alkyl group as well as polar OH^– group.

Question 5.
How the redox reactions are balanced by ion – electron method?
Answer:
The redox reactions are balanced by ion – electron method are as follows:
1. Indicate oxidation number of each element and identify the elements which undergoes change in oxidation number.

2. Indicate increase and decrease in oxidation number per atom. Multiply the increase or decrease in oxidation number with number of atoms undergoing the change.

3. Multiply the formula with suitable integer to equalise the increase and decrease in oxidation number.

4. Balance O atoms:
K₂Cr₂O₇ + 6HCl + xHCl → 2KCl + 2CrCl₃ + yCl₂ + H₂O + 6H₂O

5. Balance H atoms:
K₂Cr₂O₇ + 6HCl + 8 HCl → 2KCl + 2CrCl₃ + 3Cl₂ + 7H₂O
Here x = 8 and y = 3 to balance Cl atoms
K₂Cr₂^2-O₇ + 14 HCl → 2KCl + 2rCl₃ + 3Cl₂ + 7H₂O.
Example 2. Cr₂O₇^2- + Fe²⁺ + H⁺ → Cr³⁺ + Fe³⁺ + H₂O.
Solution:
Step 1. (Cr₂O₇)^2- + Fe²⁺ + H⁺ → Cr³⁺ + Fe³⁺ + H₂O.

Step 2.

Step 3.
Multiply Fe by 6 to equalise increase or decrease in O.N.
Cr₂O₇^2- + 6Fe²⁺ + H⁺ → Cr³⁺ + Fe³⁺ + H₂O

Step 4.
Balance atoms other than O and H
Cr₂O₇^2- + 6Fe²⁺ + H⁺ → 2Cr³⁺ + 6Fe³⁺ + H₂O

Step 5.
Balance O atoms
Cr₂O₇^2- + 6Fe²⁺ + H⁺ → 2Cr³⁺ + 6Fe³⁺ + H₂O + 6H₂O

Step 6.
Balance H atoms
Cr₂O₇^2- + 6Fe²⁺ + 14H⁺ → 2Cr³⁺ + 6Fe³⁺ + 7H₂O.

Question 6.
On the basis of electrode potential values given below? Determine reaction between reactants will occur or not?

Answer:
For feasibility of any reaction E° = +ve.
E°_cell = E°_cathode – E°_anode
(a) Fe³⁺_(aq) and I^–_(aq):
2Fe³⁺ + 2I^–_(aq) → 2Fe²⁺_(aq) + 2I_2g
Half cell reaction (oxidation)
2I^–_(aq) → I_2(g) + 2e^– E° = – 0.54 V
Reducion half cell,
2Fe³⁺_(aq) + 2e^– → 2Fe²⁺_(aq) E° = +0.77 V
Complete reaction,
2Fe³⁺_(aq) + 2I^–_(aq) → 2Fe²⁺_(aq) + I_2(g) E°_cell = +0.23 V
E° = +ve, reaction is feasible.

(b) Ag⁺_(aq) and Cu_(s)²⁺:
2Ag_(aq) + Cu_(s) → Cu²⁺_(aq) + 2Ag_(aq)
Oxidation half reaction,
Cu_(s) → Cu²⁺_(aq) + 2e^– E° = – 0.34 V
Reduction half reaction,
2Ag⁺_(aq) + 2e^– → 2Ag_(s) E° = – 0.80 V
Complete reaction,
Cu_(s) + 2Ag⁺_(aq) → Cu²⁺_(aq) + 2Ag_(s) E°_cell = +0.46 V

Question 7.
Give the main characteristics of electrochemical series?
Answer:
The main characteristics of electrochemical series are:

1. Tendency to loose electron becomes greater and the corresponding element or ion behaves as strong reducing agent if it has greater negative value of E°.
2. The substances above hydrogen are weak oxidising agents and substances below it are strong oxidising agents.
3. If the reducing agent of electrode pair is strong reducing agent, its oxidising agent is weak and when reducing agent of electrode pair is weak, its oxidising agent is strong.
4. In series the reducing efficiency decreases from above to downwards.
5. The more the positive value of E°(MPBoardSolutions.com) the stronger is its oxidising properties. In the series the oxidising power of cation decreases as we move upwards from downwards.
6. In series the electropositive character of metals decreases from upwards to downwards.
7. Along the series the electronegative character of non – metal increases from upward to downwards.
8. The metals which come prior to hydrogen displaces hydrogen from acids,
9. The metals which occupy higher position in the series displaces metals which come later in series from their salt solution.

Question 8.
Balance the equation by oxidation number method and identify the oxidising agent and reducing agent?
Cl₂O_7(g) → ClO₂^–_(aq) + O_2(g).
Answer:
Oxidation number method:

Balance the increase and decrease in O.N. multiply H₂O₂ by 4,
Cl₂O₇ + 4H₂O₂ → ClO₂^– + O₂
Balance atom other,
Cl₂O_7(g) + 4H₂O_2(aq) → 2ClO₂^–_(aq) + 4O_2(g)
Balance ‘H’,
Cl₂O_7(g) + 4H₂O_2(aq) + 2OH^–_(aq) → 2ClO₂^–_(aq) + 4O_2(g) + 5H₂O.

Question 9.
Whenever a reaction between an oxidizing agent and a reducing agent is carried out compound of lower oxidation state is formed if the reducing agent is ¡n excess and compound of higher oxidation state is formed if the oxidising agent is in excess. Justify this statement by giving three illustrations?
Answer:
1. Let us consider the reaction between carbon and oxygen.
Reducing agent + Oxidising agent

2. Let us consider the reaction between white phosphorous (P₄) and Cl_2(g)

3. Let us consider the reaction between sulphur and oxygen.
Reducing agent + Oxidising agent

Redox Reactions Long Answer Type Questions – II

Question 1.
Balance the following reaction by ion – electron method:
Cr₂O₇^2- + Fe²⁺ + H⁺ → Cr⁺³ + Fe⁺³.
Solution:
Cr₂O₇^2- + Fe²⁺ → Cr⁺³ + Fe⁺³ + H₂O

1. Write the oxidation number of each atom in skeleton equation.

Species undergo change is Cr and Fe.

2. Dividing the equation into two half reaction.
Cr₂O₇^2- → Cr⁺³ (Reduction half)
Fe⁺² → Fe⁺³ (Oxidation half)

3. Balancing reduction half:
(a) Balancing Cr atom,
Cr₂O₇^2- → 2Cr⁺³

(b) Adding e to make up the difference in O.N.

(Since each Cr atom gain 3e^– ∴ for 2 Cr atom 6e^–)

(iv) Balancing oxidation half:
(a) Balancing Fe atom (Balanced)
(b) Adding e^– to make up the difference in O.N.
Fe⁺² → Fe⁺³ + e^–

(v) Balancing ‘O’ atom,
Cr₂O₇^2- + 6e^– → 2Cr⁺³ + 7H₂O
Fe⁺² → Fe⁺³ + e^–

(vi) Balancing H by adding H⁺ ions to the side which is deficient on H atoms.
Cr₂O₇^2- + 6e^– + 14H⁺ → 2Cr⁺³ + 7H₂O
Fe²⁺ → Fe⁺³ + e^–

(vii) Equalising e^–,

Question 2.
To determine the oxidising power/reducing power in a solution which method is used? Explain with example?
Answer:
Determination of standard electrode potential ; To determine electrode potential of an electrode, a cell is setup using this electrode and standard hydrogen electrode. The EMF of the cell is measured with the help of a voltameter (or more accurately by potentiometer). (MPBoardSolutions.com) The electrode potential of hydrogen electrode is taken as zero. Therefore, the E.M.F. of such a cell will directly give the value for electrode potential for the given electrode at standard condition (298 K, 1M, 1 atm pressure).

1. If the deflection in galvanometer is towards metal electrode (experimental electrode) then it is anode (-ve terminal) of the cell. It is allotted negative value of standard reduction electrode potential.
For example, in the determination of E° value of zinc, zinc acts as anode and has got negative value of E°.

E°_cell = E°_cathode – E°_anode
∴ 0.76 V = 0.00V – E°_zn⁺²/Zn = -0.76V

Question 3.
What is oxidation number? Write its main rules of determination?
Answer:
Oxidation number of an element is defined as, “The residual charge left on its atom when all the other atoms are removed from the molecule as ions”. Atoms can have positive, negative or zero oxidation state depending upon their state of combination. (MPBoardSolutions.com) In fact, oxidation number is the charge assigned to the atom in a species according to some rules. It is also known as oxidation state.

Rules for assigning oxidation number:
The assignment of oxidation numbers is arbitrary and is usually governed by the following conclusions:

1. The oxidation number of an element in free state i. e., elementary state is regarded as zero. For example,
Oxidation state of hydrogen in H₂ = 0
Oxidation state of helium in He = 0
Oxidation state of sulphur in S₈ = 0
Oxidation state of sodium in Na = 0
Oxidation state of magnesium in Mg = 0

2. In a compound, the more electronegative elements are assigned negative (-) oxidation state and less electronegative elements are assigned positive (+) values. For example, in HCl as chlorine is more electronegative than hydrogen its oxidation state will have negative value while that of hydrogen will be positive.

3. In the formula of a compound, the sum of the negative oxidation states is equal to the sum of the positive oxidation states.

4. The sum of oxidation number of all the atoms in a neutral molecule is taken as zero.

5. Hydrogen has an oxidation state +1 in compounds like H₂S, H₂O, HCl, etc. Exceptionally it has the oxidation number -1 in metallic hydrides, such as NaH, CaH₂, etc.

6. Oxygen is usually assigned oxidation number -2, except in H₂O₂ and in oxide of fluorine [F₂O], in which the oxidation number -1 and +2 respectively. In all, oxidation number of oxygen is -1.

7. Fluorine being the most electronegative element is assigned oxidation number -1 in all its compounds. Other halogens also show -1 oxidation number.

8. The number of monoatomic ion in an ionic compound is equal to its electric charge. Thus, the elements of group IA of the periodic table (Li, Na, K, Rb, Cs) all have oxidation number + 1, while the alkaline earth metals of group IIA (Ca, Sr, Ba) have oxidation number + 2.

Question 4.
Balance the following reaction by ion – electron method?
Answer:
Ion – electron method:
Oxidation half equation is:

The oxidation number is balanced by adding 2 electrons as:
H₂O_2(aq) → O_2(g) + 2e^–
The charge is balanced by adding 2OH^– ions as:
H₂O_2(aq) + 2OH^–_(aq) → O_2(g) + 2e^–
The oxygen atoms are balanced by adding 2H₂O as:
H₂O_2(aq) + 20H^–_(aq) → O_2(g) + 2H₂O_(s) + 2e^– ……………… (1)
The reduction half equation is:

The Cl atoms are balanced as:
Cl₂O_7(g) → 2ClO₂^–_(aq)
The oxidation number is balanced by adding 8 electrons as:
Cl₂O_7(g) + 8e^– → 2ClO₂^–_(aq)
The charge is balanced by adding 6OH^– as:
Cl₂O_7(g) + 8e^– → 2ClO₂^–_(aq) + 6OH^–_(aq) ………………………… (2)
The balancing equation can be obtained by multiplying equation (1) with 4 and adding equation (2) to it as:
Cl₂O_7(g) + 4H₂O_2(aq) + 2OH^–_(aq) → 2ClO₂^–_(aq) + 4O_2(g) + 5H₂O_(l)

Question 5.
Write the main uses of electrochemical series?
Answer:
Electrochemical series:
When different elements and ions are arranged in increasing order of their standard electrode potentials, a series is obtained which is called electrochemical series or activity series.
The uses of electrochemical series are:
1. Electropositive character of metal:
Metal which loses electron easily from its outermost shell shows high electropositive character while the atom which loses electron with difficulty shows least electropositive character. In electrochemical series, Li shows maximum electropositive character while fluorine shows least electropositive character.

2. Comparison of reactivity of metals:
Metal having negative value of E° loses electron easily. Hence, greater the negative value of E° more is the reactivity and reducing character of a metal.

3. Knowledge of oxidizing agent and reducing agent:
Substance which gains electron and shows maximum value of standard electrode potential E° is strongest oxidizing agent. On the basis of this F is strongest oxidizing agent while Li is weakest oxidizing agent.

4. Displacement of elements:
Metal having greater tendency to form ion displaces others. Therefore, elements getting priority in the series displace ions of the elements following them. For example. When Cu turnings are added to AgNO₃ solution, Ag gets precipitated.
2AgNO_3(aq) + Cu_(s) → Cu(NO₃)_2(aq) + 2Ag_(s)

5. Electroplating:
Process of depositing layer of gold or silver on copper, brass, iron etc. is called electroplating. It makes articles lustrous and attractive.

6. Metallurgy:
More reactive metal displaces less reactive metal from their aqueous salt solution.

7. Corrosion of metals:
Destruction of metals due to action of chemicals, air and moisture is called corrosion.
e.g., iron rust in moist air. To prevent this a layer of more reactive metal like Sn or Zn is deposited on iron. Coating iron with zinc is called galvanization.

Question 6.
What information did you get from the following reaction:
(CN)_2(g) + 20H^–_(aq) → CN^–_(aq) + CNO^–_(aq) + H₂O_(l)
Answer:
(CN)_2(g) + 2OH^–_(aq) → CNO^–_(aq) + H₂O_(l).
1. Let the O.N. of C in (CN)₂ = x
2x + 2 (-3) = 0
or x = +3.

2. Let the O.N. of C in CN^– = x
x + (-3) = -1
or x = +2.

3. Let the O.N. of C in CNO^– = x
x + (-3) + (-2) = -1 or
x = +4.

Following informations obtained from above equation:

1. It is a disproportionation reaction.
2. The reaction occurs in basic medium.
3. O.N. of N in (CN)₂ is -3 and that in CN^– is -2 and in CNO^– it is -5.
4. Cyanogen (CN)₂ gets simultaneously reduced to CN^– ion as well as oxidized to cyanate, CNO^– ion.

Question 7.
The Mn³⁺ ion is unstable in solution and undergoes disproportionation to give Mn²⁺, MnO₂ and H⁺ ion. Write a balanced ionic equation for the reaction?
Answer:
The reaction is:
Mn³⁺_(aq) → Mn²⁺_(aq) + MnO_2(s) + H⁺_(aq)
Reduction half cell:
Mn³⁺_(aq) + e^– → Mn²⁺ …………. (1)
Oxidation half cell:
Mn³⁺_(aq) → Mn⁺⁴ + O_2(s) + e^–
To balance the equation added 4H⁺ in right and in left 2H₂O is added:
Mn³⁺_(aq) + 2H₂O_(l) → MnO_2(s) + e^– + 4H⁺_(aq) ……………….. (2)
Adding eqns. (1) and (2),
2Mn³⁺_(aq) + 2H₂O_(l) → Mn²⁺ + MnO_2(s) + 4H⁺_(aq)
This is last equation balanced (disproportionation reaction).

MP Board Class 11 Chemistry Important Questions

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: