Objective Questions On Solutions Chemistry (Colligative Properties and Determination of Molar Mass) for AIIMS, NEET, JEE provides a comprehensive coverage of the fundamental concepts in the fields of Solutions Chemistry. It contains a variety of questions from previous years’ AIIMS, NEET and JEE papers.

Objective Questions On Solutions Chemistry (Colligative Properties and Determination of Molar Mass)

1. If 1.5 grams of a non-volatile solute (MW = 100) is added to 200 ml pure CS2 (ρ = 1.3 g/cc) whose vapor pressure is 400 mm of Hg at 28.0°C, what is the resulting vapor pressure of the dilute solution?

a) 401.246 mm Hg

b) 398.754 mm Hg

c) 401.754 mm Hg

d) 398.246 mm Hg

Answer: 398.246 mm Hg

2. If the relative lowering of pressure of o-xylene is 0.005 due to addition of 0.5 grams of non-volatile solute in 500 grams of solvent, what is the molecular weight of the solute?

a) 21.3 g/mole

b) 23.1 g/mole

c) 32.1 g/mole

d) 1.23 g/mole

Answer: 21.3 g/mole

3. On addition of non-volatile potassium iodide in water at 298K it is noticed that vapor pressure reduces from 23.8 mm Hg to 2.0 cm Hg. What is the mole fraction of solute in the solution?

a) 0.916

b) 0.160

c) 0.084

d) 0.092

Answer: 0.160

4. When a non-volatile solute is added to a solvent what is the difference in vapor pressure expressed as a faction of original vapor pressure equal to?

a) Mole fraction of solute in vapor phase

b) Mole fraction of solvent in vapor phase

c) Mole fraction of solute in liquid phase

d) Mole fraction of solvent in liquid phase

Answer: Mole fraction of solute in liquid phase

5. When 2.0 grams of copper (II) nitrate is added to 1000 ml of pure water, by how much is the vapor pressure of water decreased, given that at 20°C the vapor pressure of pure water is 17.535 mm Hg?

a) 3.1 x 10^-4

b) 0.303

c) 0.0333

d) 0.0033

Answer: 0.0033

6. Two components A and B have their pure vapor pressures in the ratio 1 ∶ 4 and respective mole fractions in solution in ratio 1 ∶ 2. What is the mole fraction of component B in vapor phase?

a) 0.8889

b) 0.1250

c) 0.8000

d) 0.2000

Answer: 0.8889

7. Which of the following is Raoult’s law applicable to, in order to determine molar masses correctly?

a) Ionic solute in liquid

b) Non-ionic solute in dilute solution

c) Non-ionic solute in concentrated solution

d) Ionic solid in insoluble form in solvent

Answer: Non-ionic solute in dilute solution

8. What are the properties arising due to varying concentrations of solute in a given solvent, irrespective of the nature of solute with respect to the solvent?

a) Colligative properties

b) Intensive properties

c) Extensive properties

d) Solute properties

Answer: Colligative properties

9. Which of the following is a colligative property?

a) Relative lowering of fluid pressure

b) Decrease in boiling point

c) Decrease in freezing point

d) Change in volume after mixing

Answer: Decrease in freezing point

10. Which law specifically governs the relative lowering of vapor pressures in solutions?

a) van’t Hoff law

b) Boyle’s law

c) Raoult’s law

d) Amagat’s law

Answer: Raoult’s law

Categories: Solutions