Chemistry · Oct / Nov 2016 · Paper 12 · Question 26

The diagram shows the apparatus used to extract aluminium from aluminium oxide. [diagram: carbon electrodes, electrolyte, aluminium] Which statement about this process is correct?

1. AThe electrolyte is a solid mixture of aluminium oxide and cryolite.
2. BThe electrolyte is aluminium oxide dissolved in water.
3. CThe equation for the reaction at the positive electrode is Al³⁺ + 3e⁻ → Al.
4. DThe positive carbon electrodes lose mass during the process and need regular replacement.

As printed in the paper