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)

1.	61038 g mol–1	2.	51022 g mol–1
3.	122044 g mol–1	4.	31011 g mol–1

Henry’s law constant for the molality of methane in benzene at 298 K is 4.27 × 10⁵ mm Hg. The solubility of methane in benzene at 298 K under 760 mm Hg is -

1. 1.78 x 10^-3

2. 1.78 x 10^-5

3. 2.98 x 10^-4

4. 3.78 x 10^-3

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:

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 molarity of H₂SO₄ solution that has a density 1.84 g/cc at 35 ^oC and contains 98 % H₂SO₄ by weight is-

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

Camphor is often used in molecular mass determination because:

1. It has a very high cryoscopic constant

2. It is volatile

3. It is a solvent for organic substances

4. It is readily available 

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