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'?
OR
Write the reaction taking place in different zones of the blast furnace to obtain Iron.

Explanation

(i) To decrease the melting point of mixture and to increase the conductivity of alumina.
(ii)
(iii) it was originally derived from the Greek word-chroma meaning colour and graphy meaning writing because it was first used for the separation of coloured substnaces into individual components. the term chromatography has lost its original meaning and teh method is widely used for separtion, purification and characterization of the components of a mixture whether coloured or colour less. .