The freezing point of depression constant (K_f ) 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 azeotropic mixture of water and ethanol boils at 78.15 ^oC. When this mixture is distilled, it is possible to obtain-

1. Pure H₂O

2. Pure C₂H₅OH

3. Pure H₂O as well as pure C₂HOH

4. Neither H₂O nor C₂H₅OH in their pure state 

The mixture that shows positive deviation from Raoult's law is-

1. Benzene + Toluene

2. Acetone + Chloroform

3. Chloroethane + Bromoethane

4. Ethanol + Acetone

The feeling of weakness and discomfort in breathing at high altitudes is based on-

Preservation of fruits against bacterial action by adding sugar is an example of-

1. Exosmosis

2. Reverse-osmosis

3. Diffusion

4. Capillary action

17.4 % (w/v) ${\mathrm{K}}_2{\mathrm{SO}}_4$ solution at 27 $°$C is isotonic to 5.85 % (w/V) NaCl solution at 27 $°$C. lf NaCl is 100 % ionised, the % ionisation of ${\mathrm{K}}_2{\mathrm{SO}}_4$ in aqueous solution is-

[At wt. of K = 39, Na = 23] :-

1. 25 %

2. 75 %

3. 50 %

4. None of the above

An aqueous solution of 2 % (w\w) non-volatile solute exerts a pressure of 1.004 bar at the normal boiling point of the solvent. Molar mass of the solute would be -

Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. The vapour pressure of a mixture of 26.0 g of heptane and 35 g of octane would be -

1. 43.45 kPa

2. 78.96 Pa

3. 73.43 kPa 

4. 65.72 Pa

The mass of a non-volatile solute (molar mass 40 g mol^–1) that should be dissolved in 114 g octane
to reduce its vapour pressure to 80 % would be-

1. 6 g

2. 7 g

3. 8 g

4. 10 g

A 5 % solution (by mass) of cane sugar in water has freezing point of 271 K. Freezing point of 5 % glucose in water would be -

(freezing point of pure water is 273.15 K)

1. 279.24 K

2. - 269.06 K

3. 275. 42 ^oC

4. 269.06 K