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

1. Exosmosis

2. Reverse-osmosis

3. Diffusion

4. Capillary action

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

If the density of lake water is 1.25 g mL^–1 and contains 92 g of Na⁺ ions per kg of water, then the molality of Na⁺ ions will be-

Benzene and toluene form an ideal solution over the entire range of composition. The vapour pressure of pure benzene and toluene at 300 K are 50.71 mm Hg and 32.06 mm Hg respectively.

The mole fraction of benzene in vapour phase, if 80 g of benzene is mixed with 100 g of toluene, would be -

1. 0.41

2. 0.68

3. 0.72

4. 0.59

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

The unit that relates concentration of solution with its vapour pressure is: 

A beaker contains a solution of substance 'A' . Precipitation of substance ‘A’ takes place when small amount of 'A' is added to the solution. The solution is -

1. Saturated.

2. Supersaturated.

3. Unsaturated.

4. Concentrated.