A 0.1 molal aqueous solution of a weak acid (HA) is 30 % ionized. If K_f 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:

(Use: R = 0.083 L bar mol^–1 K^–1)

Calculate the vapour pressure of a solution prepared by mixing 25.5 g of chloroform (CHCl₃) and 40 g of dichloromethane (CH₂Cl₂) at 25°C.

Given:
Vapour pressure of pure CHCl₃ = 200 mmHg
Vapour pressure of pure CH₂Cl₂ = 415 mmHg
Molar mass of CHCl₃ = 119.5 g mol⁻¹
Molar mass of CH₂Cl₂ = 85 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 K_f and K_b 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

A solution has a 1:4 mole ratio of pentane to hexane.
The vapor pressures of the pure hydrocarbons at 20 ºC are
440 mm Hg for pentane and 120 mm Hg for hexane.
The mole fraction of pentane in the vapor phase would be:

The addition of water vapour does not change the density of:

1. CCl₄

2. CS₂

3. Ether

4. Coke

1 % (w/w) solution of a compound is isotonic with 5 % (w/w) sucrose (sugar) solution. The molecular weight of the compound will be:

The vapour pressure of a solvent decreased by 10 mm of Hg when a non-volatile solute was added to the solvent. The mole fraction of the solute in solution is 0.2. What would be the mole fraction of the solvent if the decrease in vapour pressure is 20 mm of Hg:
1. 0.2
2. 0.4
3. 0.6
4  0.8

Which colligative property provides the most accurate method for determining the molecular weight of proteins and polymers?

1. Osmotic pressure

2. Lowering of vapour pressure 

3. Lowering of freezing point

4. Elevation in boiling point