Give one word or a phrase for the statement : The process by which sulphide ore is concentrated.

Fill in the blank with the correct choice given in the bracket - The most common ore of iron is ……………[calamine/haematite]

Complete the following by selecting the correct option from the choices given –

(i) The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction …………… [Fe/Mg/Pb/Al]

(ii) The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is …………… [Al/Na/Mg/K]

Answer the following questions with respect to the electrolytic process – in the extraction of aluminium.

(i) Identify the components of the electrolyte other than pure alumina and the role played by each.

(ii) Explain why powdered coke is sprinkled over the electrolytic mixture.