Give reasons for the following – pertaining to Hall Herault’s proc

1.	Give reasons for the following – pertaining to Hall Herault’s process. It is preferred to use a number of graphite electrodes as anode, instead of a single graphite electrode.
Answer» The graphite[carbon] anodes are continously replaced during the electrolysis because : (a) The oxygen evolved at the anode escapes as a gas or reacts with the carbon anode. (b) The carbon anode is thus oxidised to carbon monoxide which either bums giving carbon dioxide or escapes out through an outlet. 2C + O₂ → 2CO [2CO + O₂ → 2CO₂] (c) The carbon anode is hence consumed and renewed periodically after a certain period of usage,

Give reasons for the following – pertaining to Hall Herault’s process. It is preferred to use a number of graphite electrodes as anode, instead of a single graphite electrode.

Answer»

The graphite[carbon] anodes are continously replaced during the electrolysis because :

(a) The oxygen evolved at the anode escapes as a gas or reacts with the carbon anode.

(b) The carbon anode is thus oxidised to carbon monoxide which either bums giving carbon dioxide or escapes out through an outlet.

2C + O₂ → 2CO [2CO + O₂ → 2CO₂]