1. For a dilute solution, Raoult’s law states that

(a) the lowering of vapour pressure is equal to the mole fraction of the solute

(b) the relative lowering of vapour pressure is equal to the mole fraction of the solute

(c) the relative lowering of vapour pressure is proportional to the amount of the solute in solution.

(d) the vapour pressure of the solution is equal to the mole fraction of the solvent

2. The molal elevation constant is the ratio of the elevation in B.P. to

(a) molarity                              (b) molality

(c) mole fraction of solute         (d) mole fraction of solvent.

3. The osmotic pressure of a 5% solution of cane sugar at 150°C is (Mol. Wt. of cane sugar = 342)

(a) 4 atm.          (b) 3.4 atm.

(c) 3.55 atm.      (d) 2.45 atm.

4. Which of the following compounds corresponds Van’t Hoff factor (i) to be equal to 2 for dilute solution?

5. 100 mL of liquid A was mixed with 25 mL of liquid B to give a non-ideal solution of A-B mixture. The volume of this mixture would be

(a) 75 mL             (b) 125 mL

(c) close to 125 mL but not exceeding 125 mL    (d) just more than 125 mL.

6. Which of the following solutions will have the highest boiling point?

(a) 1% glucose         (b) 1% sucrose

(c) 1% NaCl             (d) 1% CaCl . 2

7. The osmotic pressure of 1 m solution at 27°C is

(a) 2.46 atm     (b) 24.6 atm

(c) 1.21 atm     (d) 12.1 atm.

8. Very dilute solutions which show deviations (positive or negative) from Raoult’s law are called

(a) ideal solutions           (b) true solutions

(c) non-ideal solutions    (d) colloidal solutions.

9. 0.01 M solution each of urea, common salt and Na2SO4 are taken. The ratio of depression of freezing point is

(a) 1:1:1        (b) 1:2:1

(c) 1:2:3        (d) 2:2:3

10. The relative lowering of vapour pressure is equal to the mole fraction of the solution. This law is called

(a) Henry’s law         (b) Raoult’s law

(c) Ostwald’s law      (d) Arrhenius law.

11. A X molal solution of a compound in benzene has mole fraction of solute equal to 0.2. The value of X is

(a) 14          (b) 3.2

(c) 1.4         (d) 2.

12. Molal depression constant for water is 1.86°C. The freezing point of a 0.05 molal solution of a non-electrolyte in water is

(a) –1.86°C       (b) –0.93°C

(c) –0.093C       (d) 0.93°C.

13. When mercuric iodide is added to the aqueous solution of potassium iodide, the

(a) freezing point is raised          (b) freezing point does not change

(c) freezing point is lowered       (d) boiling point does not change.

16. The freezing point of 1 molal NaCl solution assuming NaCl to be 100% dissociated in water is

(a) –1.86°C          (b) –3.72°C

(c) + 1.86°C        (d) + –3.72°C.

18. Which one of the following pairs of solution can we expect to be isotonic at the same temperature?

19. Vapour pressure of a solution of 5 g of a non-electrolyte in 100 g of water at a particular temperature is 2985 2 N/m² . The vapour pressure of pure water is 3000 2 N/m² , the molecular weight of the solute is

(a) 60        (b) 120

(c) 180      (d) 380.

20. 0.15 g of a substance dissolved in 15 g of a solvent boiled at a temperature higher by 0.216°C than that of the pure solvent. Find out the molecular weight of the substance. (  for solvent is 2.16°C). 

(a) 1.01          (b) 10.1

(c) 100           (d) 10.

21. A 5% solution of cane sugar (Mol. Wt. = 342) is isotonic with 1% solution of substance X. The molecular weight of X is

(a) 17.12           (b) 68.4

(c) 34.2             (d) 136.2.

22. Which of the following statements is correct, if the intermolecular forces in liquids A, B

and C are in the order A < B < C?

(a) B evaporates more readily than A            (b) B evaporates less readily than C

(c) A and B evaporate at the same rate         (d) A evaporates more readily than C

23. The vapor pressure of a solvent decreased by 10 mm of Hg when a non-volatile solute was added to the solvent. The mole-fraction of solute in solution is 0.2. What would be the mole-fraction of solvent if decrease in vapour pressure is 20 mm of Hg?

(a) 0.8           (b) 0.6

(c) 0.4           (d) 0.2.

24. An ideal solution was obtained by mixing methanol and ethanol. If the partial vapour pressure of methanol and ethanol are 2.619 kPa and 4.556 kPa respectively, the composition of vapour (in terms of mole fraction) will be

(a) 0.634 MeOH, 0.365 EtOH           (b) 0.365 MeOH, 0.635 EtOH

(c) 0.574 MeOH, 0.326 EtOH           (d) 0.173 MeOH, 0.827 EtOH.

(a) 141.93 mm          (b) 94.39 mm

(c) 199.34 mm          (d) 143.99 mm.

3. 1 mol benzene 

(a) total vapour pressure 38 mm

(b) mol fraction of vapours of benzene above liquid mixture is 7/19

(c) positive deviation from Raoult’s law

(d) negative deviation from Raoult’s law

4. At 40°C, the vapour pressure in torr of methanol and ethanol solution is P = 119x + 135 Where x is the mol. fraction of methanol. Hence:

(a) vapour pressure of pure methanol is 119 torr.

(b) vapour pressure of pure ethanol is 135 torr.

(c) vapour pressure of equimolar mixture of each is 127 mm

(d) mixture is completely immiscible

5. Consider following cases:

I : 2 M CH3COOH solution in benzene at 27°C where there is dimer formation to the

extent of 100%

II : 0.5 M KCl aq. Solution at 27°C, which ionizes 100%; which is/are true statement(s)?

(a) both are isotonic    (b) I is hypertonic

(c) II is hypertonic      (d) none is correct

6. Consider following solutions:

I : 1 M aq. Glucose

II : 1 M aq. Sodium chloride

III : 1 M benzoic acid in benzene

IV : 1 M ammonium phosphate

Select correct statement(s):

(a) All are isotonic solutions                (b) III is hypotonic of I, II, IV

(c) I, II, IV are hypertonic of III          (d) IV is hypertonic of I, II, III

7. If PA is the vapour pressure of a pure liquid A and the mol fraction of A in the mixture of two liquids A and B is x, the partial vapour pressure of A is:

8. When mercuric iodide is added to the aqueous solution of potassium iodide, the:

(a) freezing point is raised                 (b) freezing point is lowered

(c) freezing point does not change     (d) boiling point does not change

9. Which is/are correct statement(s)?

(a) when mixture is less volatile, there is positive deviation from Raoult’s law

(b) when mixture is more volatile, there is negative deviation from Raoult’s law

(c) when mixture is less volatile, there is negative deviation from Raoult’s law

(d) when mixture is more volatile, there is positive devation from Raoult’s law

10. When a solute is added to a pure solvent, the

(a) vapour pressure of the solution becomes lower than that of the pure solvent

(b) rate of evaporation of the pure solvent is reduced

(c) solute does not affect the rate of condensation

(d) rate of evaporation of the solution is equal to the rate of condensation of the solution at a lower vapour pressure than that in the case of the pure solvent

11. According to Raoult’s law the relative decrease in the solvent vapour pressure over the

solution is equal to

(a) the mole fraction of the solvent

(b) the mole fraction of the solute

(c) the number of moles of the solute

(d) i times the mole fraction of the solute which undergoes dissociation or association in the solvent (i = van’t Hoff factor)

12. Which of the following combinations are correct for a binary solution, in which the solute as well as the solvent are liquid?

13. Which of the following statements are correct for a binary solution which shows negative

deviation from Raoult’s law?

(a) The negative deviation from linearity diminishes and tends to zero as the concentration of the solution component approaches unity

(b) When solutions form, their volumes are smaller than the sum of the volumes of their components

(c) Heat is released during the formation of the solution

(d) Heat is evolved during the formation of the solution

14. A binary liquid (AB) shows positive deviation from Raoult’s law when

15. The azeotropic solutions of two miscible liquids

(a) can be separated by simple distillation

(b) may show positive or negative deviation from Raoult’ law

(c) are supersaturated solutions

(d) behave like a single component and boil at a constant temperature

16. Which of the following is/are characteristics of hydrophilic solutions?

(a) High concentration of dispersed phase can be easily attained.

(b) Coagulation is reversible

(c) Viscosity and surface tension are nearly same as that of water

(d) The charge of the particle depends on the pH value of the medium; it may be positive, negative or neutral.

17. A substance effloresces

(a) due to the formation fo a crust on its crystal surface

(b) when its vapour pressure is greater than that of the water vapour in air

(c) till it melts

(d) when all of the above happen

19. When solute is added to a pure solvent, the

(a) vapuor pressure of the solution becomes lower than the vapors pressure of the pure solvent

(b) rate of evaporation of the pure solvent is reduced

(c) solute does not affect the rate of condensation

(d) none of these

22. At constant temperature, the osmotic pressure of a solution is

(a) directly proportional to the concentration

(b) inversely proportional to the molecular weight of the solute

(c) directly proportional to the square of the concentration

(d) directly proportional to the square root of the concentration

23. Ideal solution is formed when its components

(a) have zero heat of mixing

(b) have zero volume change

(c) obey Raoult’s law

(d) can be converted into gases

24. In the depression of freezing point experiment, it is found that

(a) The vapour pressure of the solution is less than that of pure solvent

(b) The vapour pressure of the solution is more than that of pure solvent

(c) Only solute molecules solidify at the freezing point

(d) Only solvent molecules solidify at the freezing point

25. The colligative properties of a solution are