Chemical Solutions

1

A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of 290 mm at 300 K. The vapour pressure of propyl alcohol is 200 nm. If the mole fraction of ethyl alcohol is 0.6, its vapour pressure (in mm) at the same temperature will be

  1. 300
  2. 350
  3. 360
  4. 700
2

If α is the degree of dissociation of Na2SO4, the vant Hoff’s factor (i) used for calculating the molecular mass is

  1. 1 + 2α
  2. 1 - α
  3. 1 + α
  4. 1 - 2α
3

Which one of the following aqueous solutions will exhibit highest boiling point?

  1. 0.01 M KNO3
  2. 0.015 M urea
  3. 0.01 M Na2SO4
  4. 0.015 M glucose
4

Equimolal solutions in the same solvent have

  1. Same boiling and same freezing points.
  2. Different boiling and different freezing points.
  3. Same freezing point but different boiling point.
  4. Same boiling point but different freezing point.
5

Two solutions of a substance (non electrolyte) are mixed in the following manner:

480 ml of 1.5 M first solution + 520 mL of 1.2 M second solution

What is the molarity of the final mixture?

  1. 2.70 M
  2. 1.50 M
  3. 1.344 M
  4. 1.20 M
6

Benzene and toluene form nearly ideal solutions. At 20°C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at 20°C for a solution containing 78 g of benzene and 46 g of toluene in torr is

  1. 25
  2. 37.5
  3. 50
  4. 53.5
7

In a 0.2 molal aqueous solution of a weak acid HX, the degree of ionization is 0.3. Taking Kf for water as 1.85, the freezing point of the solution will be nearest to

  1. – 0.480 °C
  2. – 0.360 °C
  3. – 0.260 °C
  4. + 0.480 °C
8

A solution at 20°C is composed of 1.5 mol of benzene and 3.5 mol of toluene. If the vapour pressure of pure benzene and pure toluene at this temperature are 74.7 torr and 22.3 torr, respectively, then the total vapour pressure of the solution and the benzene mole fraction in equilibrium with it will be, respectively:

  1. 35.0 torr and 0.480
  2. 38.0 torr and 0.589
  3. 30.5 torr and 0.389
  4. 35.8 torr and 0.280
9

18 g glucose (C6H12O6) is added to 178.2 g water. The vapour pressure of water (in torr) for this aqueous solution is:

  1. 76.0
  2. 752.4
  3. 759.0
  4. 7.6