Why anode has to be replaced from time to time during the electrolysis of alumina?

Explain why it is preferable to use a number of graphite anodes instead of a single electrode during the electrolysis of aluminium.

Explain why : A layer of powdered coke is sprinkled on the surface of the electrolyte during the electrolysis of molten aluminium

The metal anode has to be replaced periodically.

Give reason why : Is a neutral gas other than oxygen formed at the anode during electrolysis of fused alumina ?

Write a balanced chemical equation for - (i) The formation of aluminium at the cathode, during the electrolysis of alumina. (ii) Action of heat on aluminium hydroxide.

Oxygen and hydrogen gas are produced at the anode and cathode during the electrolysis of fairly concentration aqueous solution of :

Explain the following: A neutral gas other than oxygen is formed at the anode during electrolysis of fused alumina.

Give the products available on the cathode and the anode respectively during the electrolysis of an aqueous solution of MgSO_(4) between inert electrodes.

State the observations at the anode and at the cathode during the electrolysis of : fused lead bromide using graphite electrodes.

State the observations at the anode and at the cathode during the electrolysis of : copper sulphate solution using copper electrodes.