Answer the Following:
(i) What si the role of cryolite in the metallurgy of aluminium?
(ii) Differentiate between roasting and calcination.
(iii) What is meant by the term 'chromatography'?

Explanation

The term chromatography was originally derived from the greek word chroma meaning colour and graphy meaning writing because the method was first used for the separation of coloured substances (plant pigments) into individual components. Now the term chromatography has lost its original meaning and the method is widely used for separation, purification, identification and characterisation of the components of a mixture whether coloured or colourless.