Explain why in the electrolysis of alumina using the Hall Heroult's process the electrolyte is covered with powdered coke.

Fill in the blanks from the choices given :

Metals are good …………… [oxidizing agents / reducing agents] because they are electron …………… [acceptors/donors].

Identify the term in the following :

'The method used to separate ore from gangue by preferential wetting.'

(i) Name the solution used to react with Bauxite as a first step in obtaining pure aluminium oxide, in the Baeyer's process.

(ii) Write the equation for the reaction where the aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.

(iii) Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

(iv) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.

(v) Explain why it is preferable to use a number of graphite electrodes as anode instead of a single electrode, during the above electrolysis.