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With reference to the Hall–Héroult method used for extracting aluminium, identify the statement that is incorrect.

1. Al3+ ions gain electrons at the cathode to yield aluminium metal
2. Na3AlF6 acts as the electrolyte
3. Carbon monoxide and carbon dioxide are formed during the process
4. Al2O3 is combined with CaF2, which reduces the melting point of the melt and improves conductivity

Correct answer: Na3AlF6 acts as the electrolyte

Solution

The statement is incorrect because Na3AlF6, also known as cryolite, is not the electrolyte itself; rather, it is used to dissolve alumina (Al2O3) and facilitate the electrolysis process in the Hall–Héroult method.

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