Explain why :
In the electrolysis of alumina using the Hall Heroult's Process, the electrolyte is covered with powdered coke.

Explanation

(ii) (1) To reduce the heat loss by radiation and to prevent burning of anode in air at the point above the electrolyte.
(2) Iron sheets are coated with zinc during galvanization to prevent them from rusting as zinc is more electropositive than iron.