Solutions

The correct option for the value of vapour pressure of a solution at 45 C with benzene to octane in molar ratio 3 : 2 is : [At 45 C vapour pressure of benzene is 280 mm Hg and that of octane is 420 mm Hg. Assume ideal solution]

1. 350 mm of Hg
2. 160 mm of Hg
3. 168 mm of Hg
4. 336 mm of Hg

The freezing point depression constant (Kf) of benzene is 5.12 K kg mol-1. The freezing point depression for the solution of molality 0.078 m containing a non-electrolyte solute in benzene is rounded off upto two decimal places :

1. 0.80 K
2. 0.40 K
3. 0.60 K
4. 0.20 K

The mixture which shows positive deviation from Raoult's law is :

1. Benzene + Toluene
2. Acetone + Chloroform
3. Chloroethane + Bromoethane
4. Ethanol + Acetone

For an ideal solution, the correct option is :

1. mix H = 0 at constant T and P
2. mix G = 0 at constant T and P
3. mix S = 0 at constant T and P
4. mix V 0 at constant T and P

The mixture that forms maximum boiling azeotrope is :

1. Ethanol + Water
2. Acetone + Carbon disulphide
3. Heptane + Octane
4. Water + Nitric acid

If molality of the dilute solution is doubled, the value of molal depression constant (Kf) will be

1. halved
2. tripled
3. unchanged
4. doubled.

Which of the following is dependent on temperature?

1. Molarity
2. Mole fraction
3. Weight percentage
4. Molality

Which of the following statements about the composition of the vapour over an ideal 1 : 1 molar mixture of benzene and toluene is correct? Assume that the temperature is constant at 25 . (Given, vapour pressure data at 25 , benzene = 12.8 kPa, toluene = 3.85 kPa)

1. The vapour will contain equal amounts of benzene and toluene.
2. Not enough information is given to make a prediction.
3. The vapour will contain a higher percentage of benzene.
4. The vapour will contain a higher percentage of toluene

At 100 the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If Kb = 0.52, the boiling point of this solution will be

1. 102
2. 103
3. 101
4. 100

The van't Hoff factor (i) for a dilute aqueous solution of the strong electrolyte barium hydroxide is

1. 0
2. 1
3. 2
4. 3