The vapour density of undecomposed N₂O₄ is 46. When heated, vapour density decreases to 24.5 due to its dissociation to NO₂. The percent dissociation of N₂O₄ at the final temperature is: 

1. 87                                         

2. 60

3. 40                                         

4. 70

At 298 K, 500cm³ H₂O dissolved 15.30 cm³ CH₄(STP) under a partial pressure of methane of one atm. If Henry's law holds, what pressure is required to cause 0.001 mole methane to dissolve in 300cm³ water ?

1. 0.29 atm

2. 2.33 atm

3. 1.29 atm

4. 3.11 atm

The molal depression constant for water=1.85 deg/molal and for benzene is 5.12 deg/molal. If the ratio of the latent heats of fusion of benzene to water is 3:8, calculate the freezing point of benzene.

1. 6.75$°\mathrm{C}$

2. 5.12$°\mathrm{C}$

3. 8.97$°\mathrm{C}$

4. 6.1$°\mathrm{C}$

Which of the following colligative properties is associated with the concentration term 'molarity'?

1. Lowering of vap.pressure

2. Osmotic pressure

3. Depression in freezing point

4. Elevation in boiling point

The vapour pressure of a dilute aqueous solution of glucose is 750 mm of Hg at 373 K. The mole fraction of solute in the solution is-
1. 1/10
2. 1/76
3. 1/7.6
4. 1/35

Which pair of solutions is likely to exhibit isotonicity at a constant temperature?

Which of the following aqueous solution has osmotic pressure nearest to that an equimolar solution of K₄[Fe(CN)₆]?

1. Na₂SO₄

2. BaCl₂

3. Al₂(SO₄)₃

4. C₁₂H₂₂O₁₁

The molar volume of liquid benzene (density= 0.877 g ml^-1) increases by a factor of 2750 as it vapourises at 20$°\mathrm{C}$. At 27$°\mathrm{C}$ when a non-volatile solute (that does not dissociate) is dissolved in 54.6cm3 of benzene, vapour pressure of this solution, is found to be 98.88 mm Hg. calculate the freezing point of the solution.

Given: Enthalpy of vapourisation of benzene(l)=394.57 Jg^-1. Enthalpy of fusion of benzene (l) = 10.06 kJ mol^-1 Molal depression constant for benzene=5.0 K kg mol^-1.

1. 177.65 K

2. 277.65 K

3. 517.65 K

4. 237.15 K

The depression in the freezing point of water when 10 g of CH₃CH₂CHClCOOH is added to 250 g of water is -K_a=1.4 X 10^-3, K_f=1.86K kg mol^-1

1. 0.15$°\mathrm{C}$

2. 2.15$°\mathrm{C}$

3. 1.15$°\mathrm{C}$

4. 0.65$°\mathrm{C}$

The ratio of the vapour pressure of a solution to the vapour pressure of the solvent is

1. Equal to the mole fraction of the solvent

2. Proportional to the mole fraction of the solute

3. Equal to the mole fraction of the solute

4. None of the above