Question

Why do the carbon anodes need to be replaced regularly in the electrolysis of Al2O3 into aluminum metal?

A) They get oxidized into carbon monoxide and carbon dioxide by the oxygen molecules generated on the electrode.
B) The intense heat for the reaction breaks them apart.
C) They become saturated with aluminum metal.
D) They get oxidized by air in the intense heat of the reaction.

Answer 1

A) They get oxidized into carbon monoxide and carbon dioxide by the oxygen molecules generated on the electrode.

Step-by-step explanation:

In the electrolysis of Aluminium, the oxygen reacts with the carbon anodes forming carbon dioxide. That is, the anodes are oxidized. To ensure that the reaction completes, the anode must gradually be replaced as the reaction proceeds. The correct option is hence;

A) They get oxidized into carbon monoxide and carbon dioxide by the oxygen molecules generated on the electrode.