Outline the principles of refining of metals by the following methods :
(a) Electrolytic refining
(b) Zone refining
( c) Vapour phase refining.

Explanation

(a) The impurities are more soluble in the melt than in the solid state of the metal.
(b) Impure metal is made to act as anode, while the strip of same metal in pure form as cathode.