# During the electrolysis of copper sulfate solution, copper is deposited at the negative electrode and oxygen is produced at the positive electrode. Explain why each product forms at its respective electrode.

> AQA GCSE Chemistry (8462) — 4.4.3 Electrolysis · Explain · 4 marks

> Copper sulfate solution contains copper ions (Cu²⁺), sulfate ions (SO₄²⁻), hydrogen ions (H⁺) and hydroxide ions (OH⁻).

## Mark scheme (4 marks)

1. Copper ions (Cu²⁺) are positively charged and move to the negative electrode (cathode)
2. At the negative electrode, copper ions gain electrons and are reduced to form copper metal
3. Hydroxide ions (OH⁻) are negatively charged and move to the positive electrode (anode)
4. At the positive electrode, hydroxide ions lose electrons and are oxidised, producing oxygen gas

## Key terms

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

## Related

- [Revision notes for AQA GCSE Chemistry (8462)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/during-the-electrolysis-of-copper-sulfate-d8941ca1) · Published by Druglandscape Ltd.