NCERT Exemplar for Class 12 Chemistry Chapter 2

The Ncert exemplar class 12 chemistry Chapter 2  is a comprehensive study material prepared by the subject matter experts. These help students learn all the topics from different chapters in a detailed way. Students will gain deep insights of all the sections and prepare you for the upcoming 12th board examination. As we know, Chemistry requires attention to minor points and information, therefore, by solving exemplars students can recall, memorise, analyse and comprehend better.

This is an effective way to increase confidence in them and this will result in better performance. The given exemplar contains MCQs of two different types, Short Answer Type Questions, and Matching Types questions, there are a total of 50 questions asked. Students can access the NCERT exemplar for class 12 chemistry, Chapter 2: Solutions by scrolling below. Along with this, there are several NCERT exemplar for class 12 science of all the chapters provided on this platform.

Access the NCERT Exemplar Class 12 Chemistry Chapter 2 Solutions

I. NCERT Exemplar class 12 chemistry Chapter 2 – Multiple-choice Questions (Type-I)

Question 1

Which of the following units is useful in relating the concentration of a solution with its vapor pressure?

(a) Mole fraction
(b) Parts per million
(c) Mass percentage
(d) Molality

Solution: Option (a) is the answer.

Question 2

On dissolving sugar in water at room temperature, the solution feels cool to touch. Under which of the following cases will the dissolution of sugar be most rapid?

(a) Sugar crystals in cold water
(b) Sugar crystals in hot water
(c) Powdered sugar in cold water
(d) Powdered sugar in hot water

Solution: Option (d) is the answer.

Question 3

At equilibrium, the rate of dissolution of a solid solute in a volatile liquid solvent is __________.

(a) Less than the rate of crystallization
(b) Greater than the rate of crystallization
(c) Equal to the rate of crystallization
(d) Zero

Solution: Option (c) is the answer.

Question 4

A beaker contains a solution of a substance ‘A’. Precipitation of substance ‘A’ takes place when a small amount of ‘A’ is added to the solution. The solution is __________.

(a) Saturated
(b) Supersaturated
(c) Unsaturated
(d) Concentrated

Solution: Option (b) is the answer.

Question 5

The maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon __________.

(a) Temperature
(b) Nature of solute
(c) Pressure
(d) Nature of solvent

Solution: Option (c) is the answer.

Question 6

Low concentration of oxygen in the blood and tissues of people living at high altitude is due to __________.

(a) Low temperature
(b) Low atmospheric pressure
(c) High atmospheric pressure
(d) Both low temperature and high atmospheric pressure

Solution: Option (b) is the answer.

Question 7

Considering the formation, breaking, and strength of hydrogen bonds, predict which of the following mixtures will show a positive deviation from Raoult’s law?

(a) Methanol and acetone
(b) Chloroform and acetone
(c) Nitric acid and water
(d) Phenol and aniline

Solution: Option (a) is the answer.

Question 8

Colligative properties depend on __________.

(a) The nature of the solute particles dissolved in the solution.
(b) The number of solute particles in solution.
(c) The physical properties of the solute particles dissolved in the solution.
(d) The nature of solvent particles.

Solution: Option (b) is the answer.

Question 9

Which of the following aqueous solutions should have the highest boiling point?

(a) 1.0 M NaOH
(b) 1.0 M Na2SO4
(c) 1.0 M NH4NO3
(d) 1.0 M KNO3

Solution: Option (b) is the answer.

Question 10

The unit of the ebullioscopic constant is __________.

(a) K kg mol–1 or K (molality)–1
(b) Mol kg K–1 or K–1(molality)
(c) Kg mol–1 K–1 or K–1(molality)–1
(d) K mol kg–1 or K (molality)

Solution: Option (a) is the answer.

Question 11

In comparison to a 0.01 M solution of glucose, the depression in the freezing point of a 0.01 M MgCl2 solution is __________.

(a) The same
(b) About twice
(c) About three times
(d) About six times

Solution: Option (c) is the answer.

Question 12

An unripe mango, placed in a concentrated salt solution to prepare pickle, shrivels because __________.

(a) It gains water due to osmosis.
(b) It loses water due to reverse osmosis.
(c) It gains water due to reverse osmosis.
(d) It loses water due to osmosis.

Solution: Option (d) is the answer.

Question 13

At a given temperature, the osmotic pressure of a concentrated solution of a substance __________.

(a) Is higher than that of a dilute solution.
(b) Is lower than that of a dilute solution.
(c) Is the same as that of a dilute solution.
(d) Cannot be compared with the osmotic pressure of a dilute solution.

Solution: Option (a) is the answer.

Question 14

Which of the following statements is false?

(a) Two different solutions of sucrose of the same molality prepared in different solvents will have the same depression in the freezing point.
(b) The osmotic pressure of a solution is given by the equation Π = CRT (where C is the molarity of the solution).
(c) The decreasing order of osmotic pressure for 0.01 M aqueous solutions of barium chloride, potassium chloride, acetic acid, and sucrose is BaCl2 > KCl > CH3COOH > sucrose.
(d) According to Raoult’s law, the vapor pressure exerted by a volatile component of a solution is directly proportional to its mole fraction in the solution.

Solution: Option (a) is the answer.

Question 15

The values of Van’t Hoff factors for KCl, NaCl, and K2SO4, respectively, are __________.

(a) 2, 2, and 2
(b) 2, 2, and 3
(c) 1, 1, and 2
(d) 1, 1, and 1

Solution: Option (b) is the answer.

Question 16

Which of the following statements is false?

(a) Units of atmospheric pressure and osmotic pressure are the same.
(b) In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.
(c) The value of the molal depression constant depends on the nature of the solvent.
(d) Relative lowering of vapor pressure is a dimensionless quantity.

Solution: Option (b) is the answer.

Question 17

The value of Henry’s constant

$K_H$

__________.

(a) Increases with an increase in temperature.
(b) Decreases with an increase in temperature.
(c) Remains constant.
(d) First increases then decreases.

Solution: Option (a) is the answer.

Question 18

The value of Henry’s constant

$K_H$

is __________.

(a) Greater for gases with higher solubility.
(b) Greater for gases with lower solubility.
(c) Constant for all gases.
(d) Not related to the solubility of gases.

Solution: Option (b) is the answer.

Question 19

Consider Fig. 2.1 and mark the correct option.

(a) Water will move from the side (A) to side (B) if a pressure lower than the osmotic pressure is applied on piston (B).
(b) Water will move from the side (B) to side (A) if a pressure greater than the osmotic pressure is applied on piston (B).
(c) Water will move from the side (B) to side (A) if a pressure equal to the osmotic pressure is applied on piston (B).
(d) Water will move from the side (A) to side (B) if pressure equal to the osmotic pressure is applied on the piston (A).

Solution: Option (b) is the answer.

Question 20

We have three aqueous solutions of NaCl labeled as ‘A’, ‘B’, and ‘C’ with concentrations 0.1 M, 0.01 M, and 0.001 M, respectively. The value of Van’t Hoff factor for these solutions will be in the order __________.

(a)

$i_A < i_B < i_C$

​
(b)

$i_A > i_B > i_C$

​
(c)

$i_A = i_B = i_C$

​
(d)

$i_A < i_B > i_C$

Solution: Option (c) is the answer.

Question 21

On the basis of the information given below, mark the correct option.

Information:

(A) In bromoethane and chloroethane mixture, intermolecular interactions of A–A and B–B types are nearly the same as A–B type interactions.
(B) In ethanol and acetone mixture, A–A or B–B type intermolecular interactions are stronger than A–B type interactions.
(C) In chloroform and acetone mixture, A–A or B–B type intermolecular interactions are weaker than A–B type interactions.

(a) Solutions (B) and (C) will follow Raoult’s law.
(b) Solution (A) will follow Raoult’s law.
(c) Solution (B) will show a negative deviation from Raoult’s law.
(d) Solution (C) will show a positive deviation from Raoult’s law.

Solution: Option (b) is the answer.

Question 22

Two beakers of capacity 500 mL were taken. One of these beakers, labeled as “A”, was filled with 400 mL of water, whereas the beaker labeled “B” was filled with 400 mL of 2 M solution of NaCl. At the same temperature, both the beakers were placed in closed containers of the same material and same capacity as shown in Fig. 2.2. At a given temperature, which of the following statements is correct about the vapor pressure of pure water and that of NaCl solution?

(a) The vapor pressure in container (A) is more than that in container (B).
(b) The vapor pressure in container (A) is less than that in container (B).
(c) The vapor pressure is equal in both containers.
(d) The vapor pressure in container (B) is twice the vapor pressure in container (A).

Solution: Option (a) is the answer.

Question 23

If two liquids A and B form a minimum boiling azeotrope at some specific composition, then __________.

(a) A–B interactions are stronger than those between A–A or B–B.
(b) The vapor pressure of solution increases because more molecules of liquids A and B can escape from the solution.
(c) The vapor pressure of solution decreases because fewer molecules of only one of the liquids escape from the solution.
(d) A–B interactions are weaker than those between A–A or B–B.

Solution: Option (a) is the answer.

Question 24

4 L of 0.02 M aqueous solution of NaCl was diluted by adding one liter of water. The molality of the resultant solution is __________.

(a) 0.004
(b) 0.008
(c) 0.012
(d) 0.016

Solution: Option (d) is the answer.

Question 25

On the basis of the information given below, mark the correct option.

Information: On adding acetone to methanol, some of the hydrogen bonds between methanol molecules break.

(a) At a specific composition, the methanol-acetone mixture will form a minimum boiling azeotrope and will show a positive deviation from Raoult’s law.
(b) At a specific composition, the methanol-acetone mixture forms a maximum boiling azeotrope and will show a positive deviation from Raoult’s law.
(c) At a specific composition, the methanol-acetone mixture will form a minimum boiling azeotrope and will show a negative deviation from Raoult’s law.
(d) At a specific composition, the methanol-acetone mixture will form a maximum boiling azeotrope and will show a negative deviation from Raoult’s law.

Solution: Option (a) is the answer.

Question 26

 

$K_H$

values for

$Ar(g)$

,

$CO_2(g)$

CO2​(g),

$HCHO(g)$

and

$CH_4(g)$

are 40.39, 1.67,

$1.83 \times 10^{-5}$

and 0.413, respectively. Arrange these gases in the order of their increasing solubility.

(a) HCHO < CH4 < CO2 < Ar
(b) HCHO < CO2 < CH4 < Ar
(c) Ar < CO2 < CH4 < HCHO
(d) Ar < CH4 < CO2 < HCHO

Solution: Option (c) is the answer.

 

II. NCERT Exemplar class 12 chemistry Chapter 2 – Multiple Choice Questions (Type-II)

Note: In the following questions, two or more options may be correct.

Question 27

Which of the following factor(s) affect the solubility of a gaseous solute in a fixed volume of liquid solvent?

(a) Nature of solute
(b) Temperature
(c) Pressure

(i) (a) and (c) at constant T
(ii) (a) and (b) at constant P
(iii) (b) and (c) only
(iv) (c) only

Solution: Option (i) and (ii) are the answers.

Question 28

Intermolecular forces between two benzene molecules are near the same strength as those between two toluene molecules. For a mixture of benzene and toluene, which of the following is not true?

(a)

$\Delta_{\text{mix}} H = 0$

(b)

$\Delta_{\text{mix}} V = 0$

(c) These will form a minimum boiling azeotrope.
(d) These will not form the ideal solution.

Solution: Option (c) and (d) are the answers.

Question 29

Relative lowering of vapor pressure is a colligative property because _____________.

(a) It depends on the concentration of a non-electrolyte solute in a solution and does not depend on the nature of the solute molecules.
(b) It depends on the number of particles of electrolyte solute in a solution and does not depend on the nature of the solute particles.
(c) It depends on the concentration of a non-electrolyte solute in a solution as well as on the nature of the solute molecules.
(d) It depends on the concentration of an electrolyte or non-electrolyte solute in a solution as well as on the nature of solute molecules.

Solution: Option (a) and (b) are the answers.

Question 30

Van’t Hoff factor, 

$i$

is given by the expression _____________.

(a)

$i = \frac{\text{Normal molar mass}}{\text{Abnormal molar mass}}$

​
(b)

$i = \frac{\text{Abnormal molar mass}}{\text{Normal molar mass}}$

​
(c)

$i = \frac{\text{Observed colligative property}}{\text{Calculated colligative property}}$

(d)

$i = \frac{\text{Calculated colligative property}}{\text{Observed colligative property}}$

Solution: Option (a) and (c) are the answers.

Question 31

Isotonic solutions must have the same _____________.

(a) Solute
(b) Density
(c) Elevation in boiling point
(d) Depression in freezing point

Solution: Option (c) and (d) are the answers.

Question 32

Which of the following binary mixtures will have the same composition in the liquid and vapor phase?

(a) Benzene – Toluene
(b) Water-Nitric acid
(c) Water-Ethanol
(d) n-Hexane – n-Heptane

Solution: Option (b) and (c) are the answers.

Question 33

In isotonic solutions ________________.

(a) Solute and solvent both are the same.
(b) Osmotic pressure is the same.
(c) Solute and solvent may or may not be the same.
(d) A solute is always the same, but the solvent may be different.

Solution: Option (b) and (c) are the answers.

Question 34

For a binary ideal liquid solution, the variation in total vapor pressure versus the composition of the solution is given by which of the curves?

Solution: Option (a) and (d) are the answers.

Question 35

Colligative properties are observed when _____________.

(a) A non-volatile solid is dissolved in a volatile liquid.
(b) A non-volatile liquid is dissolved in another volatile liquid.
(c) A gas is dissolved in a non-volatile liquid.
(d) A volatile liquid is dissolved in another volatile liquid.

Solution: Option (a) and (b) are the answers.

III. NCERT Exemplar class 12 chemistry Chapter 2 Short Answer Type Questions

Question 36

Components of a binary mixture of two liquids A and B were being separated by distillation. After some time separation of components stopped and the composition of the vapour phase became the same as that of a liquid phase. Both the components started coming in the distillate. Explain why this happened.

Solution:
Both the components started coming in the distillate, and the vapor and liquid phase had the same composition. This indicates the formation of an azeotropic mixture, which cannot be separated by simple distillation.

Question 37

Explain why on the addition of 1 mol of NaCl to 1 litre of water, the boiling point of water increases, while the addition of 1 mol of methyl alcohol to one litre of water decreases its boiling point.

Solution:
On the addition of 1 mol of NaCl to 1 litre of water, the boiling point increases because NaCl is a non-volatile solute. In contrast, adding 1 mol of methyl alcohol, a volatile substance, decreases the boiling point of water.

Question 38

Explain the solubility rule “like dissolves like” in terms of intermolecular forces that exist in solutions.

Solution:
The rule “like dissolves like” means that solutes dissolve in solvents with similar intermolecular forces. Polar solutes dissolve in polar solvents, and non-polar solutes dissolve in non-polar solvents due to the similarity in their intermolecular interactions.

Question 39

Concentration terms such as mass percentage, ppm, mole fraction, and molality are independent of temperature, however, molarity is a function of temperature. Explain.

Solution:
Molarity depends on the volume of the solution, which changes with temperature. Other concentration terms, like mass percentage, ppm, mole fraction, and molality, are based on mass and are unaffected by temperature changes.

Question 40

What is the significance of Henry’s Law constant

$K_H$

KH​?

Solution:
Henry’s Law constant

$K_H$

KH​ relates the solubility of a gas in a liquid to the partial pressure of the gas above the liquid. A higher

$K_H$

KH​ value indicates lower gas solubility in the liquid at a given temperature.

Question 41

Why are aquatic species more comfortable in cold water in comparison to warm water?

Solution:
Aquatic species prefer cold water because oxygen is more soluble in cold water than in warm water, providing a higher concentration of dissolved oxygen for respiration.

Question 42

(a) Explain the following phenomena with the help of Henry’s law.

i. A painful condition known as bends.

ii. Feeling of weakness and discomfort in breathing at high altitude.

(b) Why does a soda water bottle kept at room temperature fizz on opening?

Solution:
(a – i) Bends occur when divers return to the surface too quickly, causing nitrogen, which dissolved in their blood under high pressure, to form bubbles due to reduced solubility.

(a – ii) At high altitudes, lower atmospheric pressure reduces the solubility of oxygen in the blood, leading to weakness and difficulty in breathing (anoxia).

(b) The soda water bottle fizzes on opening because the pressure inside the bottle is released, decreasing the solubility of CO₂, which escapes as bubbles.

Question 43

Why is the vapour pressure of an aqueous solution of glucose lower than that of water?

Solution:
In an aqueous glucose solution, glucose molecules occupy surface area, reducing the number of water molecules that can escape into the vapor phase, thus lowering the vapor pressure compared to pure water.

Question 44

How does sprinkling of salt help in clearing the snow-covered roads in hilly areas? Explain the phenomenon involved in the process.

Solution:
Salt lowers the freezing point of water, causing the ice to melt even at temperatures below 0°C. This process helps in clearing snow-covered roads.

Question 45

What is a “semi-permeable membrane”?

Solution:
A semipermeable membrane is a membrane that allows only the solvent molecules to pass through while preventing the passage of solute molecules. Examples include cellulose acetate and the phospholipid bilayer in biological cells.

Question 46

Give an example of a material used for making a semipermeable membrane for carrying out reverse osmosis.

Solution:
Materials like cellulose acetate and polyamides are commonly used for making semipermeable membranes used in reverse osmosis.

IV. NCERT Exemplar class 12 chemistry Chapter 2 Matching Type

Question 46

Match the items given in Column I and Column II.

Column I	Column II
1 Saturated solution	(a) Solution having the same osmotic pressure at a given temperature as that of the given solution.
2 Binary solution	(b) A solution whose osmotic pressure is less than that of another.
3 Isotonic solution	(c) Solution with two components.
4 Hypotonic solution	(d) A solution which contains the maximum amount of solute that can be dissolved in a given amount of solvent at a given temperature.
5 Solid solution	(e) A solution whose osmotic pressure is more than another.
6 Hypertonic solution	(f) A solution in the solid phase.

Solution:

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

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Question 48

Match the items given in Column I with the type of solutions given in Column II.

Column I	Column II
1 Soda water	(a) A solution of the gas in solid
2 Sugar solution	(b) A solution of gas in gas.
3 German silver	(c) A solution of solid in liquid.
4 Air	(d) A solution of solid in solid.
5 Hydrogen gas in palladium	(e) A solution of the gas in liquid.

Solution:

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

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Question 49

Match the laws given in Column I with expressions given in Column II.

Column I	Column II
1 Raoult’s law	(a) $\Delta T_f = K_f \cdot m$ΔTf​=Kf​⋅m ​
2 Henry’s law	(b) $\Pi = CRT$Π=CRT
3 Elevation of boiling point	(c) $p = x_1 P_1^0 + x_2 P_2^0$p=x1​P10​+x2​P20
4 Depression in freezing point	(d) $\Delta T_b = K_b \cdot m$ΔTb​=Kb​⋅m
5 Osmotic pressure	(e) $p = K_H \cdot x$p=KH​⋅x

Solution:

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

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Question 50

Match the terms given in Column I with expressions given in Column II.

Column I	Column II
(1) Mass percentage	(a) Number of moles of the solute component / Volume of solution in litres
(2) Volume percentage	(b) Number of moles of a component / Total number of moles of all the components
(3) Mole fraction	(c) Volume of the solute component in solution / Total volume of solution * 100
(4) Molality	(d) Mass of the solute component in solution / Total mass of the solution * 100
(5) Molarity	(e) Number of moles of the solute components / Mass of solvent in kilograms

Solution:

1.  d
2.  c
3. b
4. e
5. a

NCERT Exemplar For Class 12 Science

The NCERT exemplars are an effective study material for scoring higher marks in the examination paper. Students must practise these additional questions for their own benefits, as these are curated by the best subject-matter experts to boost both knowledge and confidence. Students can easily access the ncert exemplar for class 12 science by visiting our website SimplyAcad and solve all the questions listed to secure maximum marks.

Here are some other NCERT exemplar for class 12 chemistry:

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NCERT exemplar for class 12 chemistry Chapter 4	NCERT exemplar for class 12 chemistry Chapter 9
NCERT exemplar for class 12 chemistry Chapter 5	NCERT exemplar for class 12 chemistry Chapter 10
NCERT exemplar for class 12 chemistry Chapter 6	NCERT exemplar for class 12 chemistry Chapter 11