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 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

The lowest boiling point, if concentration is fixed at 0.1 M in aqueous solution, is given by which of the following solutions?

a. K₂SO₄

b. NaCl

c. Urea

d. Glucose

1. a, b

2. b, c

3. c, d

4. d, a

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-

Saturated solution of Ag₂SO₄ shows 0.003K rise in boiling point, K_sp will be :(K_b = 5 K kg mol^-1)(1m=1M)

1. 3.2 x 10^-11

2.  3.2 x 10^-10

3.  3.2 x 10^-9

4.  3.2 x 10^-12

At 100°C the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If K_b = 0.52, the boiling point of this solution will be

(1) 100°C

(2) 102°C

(3) 103°C

(4) 101°C

How many mili moles of sucrose should be dissolved in 500 gms of water so as to get a solution which has a difference of 103.57°C between boiling point and freezing point.

(K₁ = 1.86 K Kg mol⁻¹, K_b = 0.52 K Kg mo1⁻¹)

(1) 500 mmoles

(2) 900 mmoles

(3) 750 mmoles

(4) 650 mmoles