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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.
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Solution
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 \[\ce{CO2}\].
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