The freezing point of 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 up to 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
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-
1. | Boyle's law | 2. | Charles's law |
3. | Henry's law | 4. | Raoult's law |
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) solution at 27 C is isotonic to 5.85 % (w/V) NaCl solution at 27 C. lf NaCl is 100 % ionised, the % ionisation of 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:
1. | 23.69 g mol–1 | 2. | 41.35 g mol–1 |
3. | 56.23 g mol–1 | 4. | 22.76 g mol–1 |
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