Question

(a) Define

(i) Henry's law

(ii) Crystallization.

(b) State the different methods of crystallization.

Answer 1

(a) (i)Henry’s law:It states that at any given temperatures, the mass of a gas dissolved in a fixed volume of a liquid or solution is directly proportional to the pressure on the surface of a liquid.
(ii)Crystallisation:It is the process by which crystals of a substance separate out on cooling its hot saturated solution.

(b) In the laboratory, crystals may be obtained by the following methods:

1. By cooling a hot saturated solution gently.
2. By cooling a fused mass.
3. By sublimation.
4. By evaporating slowly a saturated solution.