Write principle behind the following :
(i) Vapour phase refining
(ii) Chromatography
(iii) Froth flatation process.

Explanation

(i) The metal is converted into a volatile compound leaving non-volatile impurities behind. The volatile compound is then decomposed to give pure metal.
(ii) The different constituents in a mixed ore are adsorbed to different extent on the surface of the adsorbent.
(iii) Mineral particles are wetted by oil and gangue particles by water.