Question

In the electrolytic reduction of alumina, the electrolyte is covered with coke powder because, it __________.

• A. prevents oxidation of aluminium formed
• B. reacts with aluminium forming aluminium carbide
• C. prevents heat loss from the electrolyte
• D. none of the above

Answer 1

The correct option is C prevents heat loss from the electrolyte

The electrolytic mixture is sprinkled with coke to prevent the anode's oxidation by the oxygen evolved

Also, more material to the top of the anode is continuously added in the form of briquettes made from coke and pitch. The lost heat from the smelting operation is used to bake the briquettes into the carbon form required for reaction with alumina.

Therefore, $C$ is correct