Ncert Exercises & Solutions

Relative lowering of vapor pressure is a colligative property because:

(a)	It depends on the concentration of a non-electrolyte solute in a solution and does not depend on the nature of the solute molecules
(b)	It depends on the number of particles of electrolyte solute in a solution and does not depend on the nature of the solute particles
(c)	It depends on the concentration of a non-electrolyte solute in solution as well as on the nature of the solute molecules
(d)	It depends on the concentration of an electrolyte or non-electrolyte solute in solution as well as on the nature of solute molecules

The correct choice among the given is:

1. (a, b)

2. (b, c)

3. (c, d)

4. (a, d)

Hint: Depends upon the number of solute particles but does not depend upon the nature of the solute

Relative lowering of vapour pressure is a colligative property because

(i) It does not depend upon nature of solute.

(ii) It depends upon number of solute particles.
(ii) It depends upon concentration of non-electrolyte solution.

Hence, (a) and (b) are correct.