Solutions Questions and Answers Part-1

1. When mercuric iodide is added to the aqueous solution of potassium iodide then
a) freezing point is raised.
b) freezing point is lowered.
c) freezing point does not change
d) boiling point does not change

Answer: a
Explanation: freezing point is raised

2. Which one of the following salts will have the same value of van’t Hoff factor (i) as that of \[K_{4}\left[Fe\left( CN\right)_{6}\right]\]
a) \[Al_{2}\left(SO_4\right)_{3}\]
b) NaCl
c) \[Al \left(NO_{3}\right)_{3}\]
d) \[Na_{2}SO_{4}\]

Answer: a
Explanation: \[Al_{2}\left(SO_4\right)_{3}\]

3. 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 solute in solution
d) the vapour pressure of the solution is equal to the mole fraction of the solvent

Answer: c
Explanation: For a dilute solution, Raoult’s law states that the relative lowering of vapour pressure is proportional to the amount of solute in solution

4. The normality of 10% (weight/volume) acetic acid is
a) 1 N
b) 10 N
c) 1.7 N
d) 0.83 N

Answer: c
Explanation: The normality of 10% (weight/volume) acetic acid is 1.7 N

5. Osmotic pressure of a sugar solution at 24°C is 2.5 atmosphere. The concentration of the solution in gm mole per litre is
a) 10.25
b) 1.025
c) 102.5
d) 0.1025

Answer: d
Explanation: 0.1025

6. A solution is obtained by dissolving 12 gm of urea (mol. wt. 60) in a litre of water. Another solution is obtained by dissolving 68.4 gm of cane sugar (mol. wt. 342) in a litre of water at the same temperature. The lowering of vapour pressure in the first solution is
a) same as that of 2nd solution
b) nearly one-fifth of the 2nd solution
c) double that of 2nd solution
d) nearly five times that of 2nd solution

Answer: a
Explanation: same as that of 2nd solution

7. Freezing point of an aqueous solution is (–0.186)°C. Elevation of boiling point of the same solution is \[K_{b}=0.512°C,K_{f}=1.86°C,\]       find the increase in boiling point.
a) 0.186°C
b) 0.0512°C
c) 0.092°C
d) 0.2372°C

Answer: b
Explanation: 0.0512°C

8. The relationship between osmotic pressure at 273 K when 10g glucose \[\left(P_{1}\right)\]   , 10 g urea \[\left(P_{2}\right)\]   , and 10g sucrose \[\left(P_{3}\right)\] are dissolved in 250 ml of water is
a) \[P_{1}>P_{2}>P_{3}\]
b) \[P_{3}>P_{1}>P_{2}\]
c) \[P_{2}>P_{1}>P_{3}\]
d) \[P_{2}>P_{3}>P_{1}\]

Answer: c
Explanation: \[P_{2}>P_{1}>P_{3}\]

9. Which of the following modes of expressing concentration is independent of temperature?
a) Molarity
b) Formality
c) Normality
d) Molality

Answer: d
Explanation: Molality involves weight of solute and solvent, hence it is independent of temperature.

10. The solubility of a gas in water depends on
a) nature of the gas
b) temperature
c) pressure of the gas
d) All of these

Answer: d
Explanation: All are correct.