1.

In the electrolytic method of obtaining aluminium from purified bauxite, cryolite is added to the charge in order to

Answer»

minimise the heat LOSS due to radiation
protect aluminium produced from oxygen
 dissolve bauxite and render it conductor of electricity
 lower the melting POINT of bauxite.

Solution :(i) Pure alumina is a bad conductor of electricity
(ii) The fusion temperature of pure alumina is about `2000^(@)C` and at this temperature when the electrolysis is carried of FUSED mass, the metal formed EVAPORATES as the boiling point of aluminium is `1800^(@)C`.The above difficulties are overcome by using a mixture of alumina, cryolite and fluorspar.


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