Which of these ions is expected to be coloured in aqueous solution?

I. Fe³⁺

II. Ni²⁺

III. Al³⁺

• I and II

• II and III

• I and III

• I, II and III

52.

A 0.1 molal aqueous solution of a weak acid is 30% ionised. If K_f for water is 1.86° C/m, the freezing point of the solution will be

• -0.18$°$C

• -0.54$°$C

• -0.36$°$C

• -0.24$°$C

The freezing point of a solution composed of 10.0 g of KCl in 100 g of water is 4.5°C. Calculate the van't Hoff factor, i for this solution.

• 2.50

• 1.8

• 1.2

• 1.3

During the depression in freezing point experiment, an equilibrium is established between the molecules of

• liquid solvent and solid solvent

• liquid solute and solid solvent

• liquid solute and solid solute

• liquid solvent and solid solute

The freezing point of a 0.05 molal solution of a non- electrolyte in water is

• -0.093° C

• 1.86°C

• 0.93° C

• 0.093°C

Solutions A, B, C and D are respectively 0.1 M glucose, 0.05 M NaCl, 0.05 M BaCl₂ and 0.1 M AlCl₃. Which one of the following pairs is isotonic?

• A and B

• B and C

• A and D

• A and C

Copper is a divalent metal. The value of its electrochemical equivalent is 3.29 × 10^-4 g. Its atomic mass is

• 31.74 g

• 63.5 g

• 126.9 g

• 15.87 g

The vapour pressure of benzene at a certain temperature is 640 mm of Hg. A non-volatile and non-electrolyte solid weighing 2.175 g is added to 39.08 g of benzene. If the vapour pressure of the solution is 600 mm of Hg, what is the molecular weight of solid substance ?

• 49.50

• 59.60

• 69.60

• 79.82

Which of the following solutions will have highest boiling point ?

• 0.1 M FeCl₃

• 0.1 M BaCl₂

• 0.1 M NaCl

• 0.1 M urea (NH₂CONH₂)

Maximum depression in freezing point is caused by

• potassium chloride

• sodium sulphate

• magnesium sulphate

• magnesium carbonate