# Aluminium is extracted from its ore by electrolysis of molten aluminium oxide. Explain what happens at each electrode during this process, including the type of reaction occurring at each electrode.

> OCR GCSE Chemistry A: Gateway Science (J248) — C3.4 Electrolysis · Explain · 4 marks

> Aluminium is one of the most widely used metals in the world. It cannot be extracted by reduction with carbon because it is too reactive, so electrolysis of molten aluminium oxide is used instead. The electrodes used are inert.

## Mark scheme (4 marks)

1. Aluminium ions (Al³⁺) are positively charged ions / cations that move to the cathode (negative electrode)
2. At the cathode, aluminium ions gain electrons / are reduced to form aluminium metal
3. Oxide ions (O²⁻) are negatively charged ions / anions that move to the anode (positive electrode)
4. At the anode, oxide ions lose electrons / are oxidised to form oxygen gas

## Key terms

- [electrolysis](https://www.gradenine.co.uk/glossary/electrolysis)

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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