If BaCl₂,ionizes to an extent of 80% in aqueous solution, the value of van't Hoff factor is

• 2.6

• 0.4

• 0.8

• 2.4

X is a non-volatile solute and Y is a volatile solvent. The following vapour pressures are observed by dissolving X in Y.

X/mol L-1	Y/mm of Hg
0.10	p1
0.25	p2
0.01	p3

The correct order of vapour pressures is

• p₁ < p₂ <p₃

• p₃ < p₂ < p₁

• p₃ <p₁ < p₂

• p₂ <p₁ <p₃

Which one of the followng is an isotonic pair of solutions?

• 0.15 M NaCl and 0.11 M Na₂SO₄

• 0.2 M Urea and 0.1 M Sugar

• 0.1 M BaCl₂ and 0.2 M Urea

• 0.4 M MgSO₄ and 0.1 M NH₄Cl

384.

The vapour pressure in mm of Hg, of an aqueous solution obtained by adding 18 g of glucose (C₆H₁₂O₆) to 180g of water at 100°C is

• 76.0

• 7.60

• 759

• 752.4

The weight in grams of a non-volatile solute (mol. wt. 60) to be dissolved in 90 g of water to produce a relative lowering of vapour pressure of 0.02 is

• 4

• 8

• 6

• 10

The experimentally determined molar mass of a non-volatile solute, BaCl₂ in water by Cottrell's method, is

• equal to the calculated molar mass

• more than the calculated molar mass

• less than the calculated molar mass

• double of the calculated molar mass

Vapour pressure in mm Hg of 0.1 mole of urea in 180 g of water at 25° C is (The vapour pressure of water at 25°C is 24 mm Hg)

• 2.376

• 20.76

• 23.76

• 24.76

The molar mass of a solute X in g mol^-1, if its 1% solution is isotonic with a 5% solution of cane sugar(molar mass = 342 g mol^-1), is

• 68.4

• 34.2

• 136.2

• 171.2

18 g of glucose is dissolved in 90 g of water. The relative lowering of vapour pressure of the solution is equal to

• 6

• 0.2

• 5.1

• 0.02

The vapour pressure of pure benzene and toluene are 160 and 60 mmHg respectively. The mole fraction of benzene in vapour phase in contact with equimolar solution of benzene and toluene is

• 0.073

• 0.027

• 0.27

• 0.73