State the principles of refining of metal by the following methods. (a) Zone refining (b) Electrolytic refining (c) Vapour phase refining
(a) The principle attached with zone refining is that impurities are more soluble in molten state than in the solid state of metal. (b) The principle attached with electrolytic refining is the tendency of pure metal to deposit on the cathode by passing electricity. (c) The principle attached with vapour phase refining is that impure metal forms volatile compound which easily decomposes to pure metal on further heating.
