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 mixture that shows positive deviation from Raoult's law is-
1. Benzene + Toluene
2. Acetone + Chloroform
3. Chloroethane + Bromoethane
4. Ethanol + Acetone
If 8 g of a non-electrolyte solute is dissolved in 114 g of n-octane to reduce its vapor pressure to 80 %, the molar mass (in g mol–1) of the solute is:
[Molar mass of n-octane is 114 g mol–1]
1. | 40 | 2. | 60 |
3. | 80 | 4. | 20 |
Isotonic solutions have the same:
1. Vapour pressure
2. Freezing temperature
3. Osmotic pressure
4. Boiling temperature
The correct statement regarding a solution of two components A and B exhibiting positive deviation from ideal behaviour is :
1. | Intermolecular attractive force between A-A and B-B are stronger than those between A-B |
2. | ∆mixH = 0 at constant T and P |
3. | ∆mixV = 0 at constant T and P |
4. | Intermolecular attractive forces between A-A and B-B are equal to those between A-B |
Vapour pressure of chloroform \(\mathrm{(CHCl_3)}\) and dichloromethane \(\mathrm{(CH_2Cl_2)}\) at are 200 mmHg and 41.5 mmHg respectively. Vapour pressure of the solution was obtained by mixing 25.5 g of \(\mathrm{(CHCl_3)}\) and 40 g of \(\mathrm{(CH_2Cl_2)}\) at the same temperature will be: (Molecular mass of \(\mathrm{(CHCl_3)}\) = 119.5 u and molecular mass of \(\mathrm{(CH_2Cl_2)}\) = 85 u)
1. | 90.40 mm Hg | 2. | 119.5 mm Hg |
3. | 75 mm Hg | 4. | 173.9 mm Hg |
A 0.1 molal aqueous solution of a weak acid (HA) is 30 % ionized. If Kf for water is 1.86 °C/m, the freezing point of the solution will be:
1. | –0.24 °C | 2. | –0.18 °C |
3. | –0.54 °C | 4. | –0.36 °C |
200 mL of an aqueous solution contains 1.26 g of protein. The osmotic pressure of this solution at 300 K is found to be 2.57 × 10–3 bar. The molar mass of protein will be:
(R = 0.083 L bar mol–1 K–1):
1. | 61038 g mol–1 | 2. | 51022 g mol–1 |
3. | 122044 g mol–1 | 4. | 31011 g mol–1 |
The vapour pressure of two liquids 'P' and 'Q' are 80 and 60 torr, respectively. The total vapour pressure of the solution obtained by mixing 3 moles of P and 2 moles of Q would be:
1. 68 torr
2. 140 torr
3. 72 torr
4. 20 torr
A solution of urea (molar mass 56 g mol–1) boils at 100.18 ºC at atmospheric pressure. If Kf and Kb for water are 1.86 and 0.512 K kg mol–1 respectively, the above solution will freeze at:
1. –6.54 ºC
2. –0.654 ºC
3. 6.54 ºC
4. 0.654 ºC