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 one of the folowing pairs of solution can we expect to be isotonic at the same temperature-

1. 0.1 (M) urea and 0.1 (M) NaCl

2. 0.1 (M) urea and 0.2 (M) MgCl₂

3. 0.1 (M) NaCl and 0.1 (M) Na₂SO₄

4. 0.1 (M) Ca(NO₃)₂ and 0.1 (M) Na₂SO₄

The latent heat of vapourisation of water is 540 cal g^-1 at 100$°\mathrm{C}$. K_b for water is

1. 0.56 K.mole^-1

2. 1.86 K.mole^-1

3. 0.51 K.mole^-1

4. 5.12 K.mole^-1

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

Mole fraction of the component A in vapour phase is X₁ and mole fraction of component A in liquid mixture is X₂ then 

(${\mathrm{P}}_{\mathrm{A}}^0$ = vapour pressure of pure A; ${\mathrm{P}}_{\mathrm{B}}^0$= vapour pressure of pure B),

then total vapour pressure of the liquid mixture is-

1. $\frac{{\mathrm{P}}_{\mathrm{A}}^0{\mathrm{X}}_2}{{\mathrm{X}}_1}$

2. $\frac{{\mathrm{P}}_{\mathrm{A}}^0{\mathrm{X}}_1}{{\mathrm{X}}_2}$

3. $\frac{{\mathrm{P}}_{\mathrm{B}}^0{\mathrm{X}}_1}{{\mathrm{X}}_2}$

4. $\frac{{\mathrm{P}}_{\mathrm{B}}^0{\mathrm{X}}_2}{{\mathrm{X}}_1}$