Question

In the metallurgy of aluminium ______.

Options

• \[\ce{Al^{3+}}\] is oxidised to \[\ce{Al(s)}\].

• graphide anode is oxidised to carbon monoxide and carbon dioxide.

• oxidation state of oxygen changes in the reaction at anode.

• oxidation state of oxygen changes in the overall reaction involved in the process.

Answer 1

In the metallurgy of aluminium graphide anode is oxidised to carbon monoxide and carbon dioxide.

Explanation:

\[\ce{2Al2O3 + 3C -> 4Al + 3CO2}\]

This process of electrolysis is widely known as Hall-Heroult process. Thus, electrolysis of the molten mass is carried out in an electrolytic cell using carbon electrodes. The oxggen liberated at anode reacts with the carbon of anode producing \[\ce{CO}\] and \[\ce{CO2}\].