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$°\mathrm{C}$

The boiling point of acetic acid is 118.1$°\mathrm{C}$ and its latent heat of vaporisation is 121 cal/gm. A solution containing 0.4344 gm anthracene in 44.16 gm acetic acid boils at 118.24$°\mathrm{C}$. What is the molecular wt. of anthracene ?

1. 122

2. 178

3. 105

4. 154

A 2.0% solution by weight of urea in water shows a boiling point elevation of 0.18 deg [Molecular weight of urea=60]. Calculate the latent heat of vaporization per gram of water.

1. 495.3 cal/g

2. 560.3 cal/g

3. 525.8 cal/g

4. 501.3 cal/g

One molal solution of a carboxylic acid in benzene shows the elevation of boiling point of 1.518 K. The degree of association for dimerisation of the acid in benzene is 

(Kb for benzene = 2.53 K kgmol^-1)

(1) 60%

(2) 70%

(3) 75%

(4) 80 %

Aluminium phosphate is 100 % ionized in 0.01 m aqueous solution. Hence, $∆{\mathrm{T}}_{\mathrm{b}}/{\mathrm{k}}_{\mathrm{b}}$ is-