A solution containing 3.3 g of a substance in 125 g of benzene (b.p. 80°C) boils at 80.66°C. If K_b for one litre of benzene is 3.28°C, the molecular weight of the substance shall be 

1. 127.20

2. 131.20

3. 137.12

4. 142.72

The molal b.p. constant for water is $0{.513}^{o}Ckgmo{l}^{-1}$. When 0.1 mole of sugar is dissolved in 200 g of water, the solution boils under a pressure of 1 atm at

(1) 100.513°C

(2) 100.0513°C

(3) 100.256°C

(4) 101.025°C

An aqueous solution containing 1 g of urea boils at 100.25 °C. The aqueous solution containing 3 g of glucose in the same volume will boil at:
1. 100.75 °C
2. 100.5 °C
3. 100 °C
4. 100.25 °C

Solution of sucrose (Mol. Mass = 342) is prepared by dissolving 34.2 gm of it in 1000 gm of water. Freezing point of the solution is (K_f for water is 1.86 K kg mol^–1) [AIEEE 2003]

(1) 272.814 K

(2) 278.1 K

(3) 273.15 K

(4) 270 K

An aqueous solution of a weak monobasic acid containing 0.1 g in 21.7 g of water freezes at 272.817K. If the value of K_f for water is 1.86 K kg mol^–1, the molecular mass of the acid is [AMU 2002]

(1) 46.0

(2) 48.6

(3) 48.8

(4) 46.8

What is the molality of the solution of a certain solute in a solvent if there is a freezing point depression of 0.184° and if the freezing point constant is 18.4 K kg mol⁻¹

1. 0.01

2. 1.00

3. 0.001

4. 100

A solution containing 6.8 g of a non-ionic solute in 100 g of water was found to freeze at −0.93 ^oC. The freezing point depression constant of water is 1.86. The molecular weight of the solute is-

The molar freezing point constant for water is 1.86°C/mole. If 342 g of cane sugar $\left({\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}\right)$ is dissolved in 1000 g of water, the solution will freeze at 

1. –1.86°C

2. 1.86°C

3. –3.92°C

4. 2.42°C

The molal freezing point constant for water is 1.86°C/m. Therefore, the freezing point of 0.1 m NaCl solution in water is expected to be [MLNR 1994]

(1) –1.86°C

(2) –0.186°C

(3) –0.372°C

(4) +0.372°C

The depression in freezing point of 0.01 M aqueous solutions of urea, sodium chloride and sodium sulphate is in the ratio of [Roorkee 1990; DCE 1994]

(1) 1 : 1 : 1

(2) 1 : 2 : 3

(3) 1 : 2 : 4

(4) 2 : 2 : 3