# Zinc powder is added to copper(II) sulfate solution. The blue colour of the solution fades and a reddish-brown solid forms. Explain why this reaction is a redox reaction, referring to the changes in oxidation state of both zinc and copper.

> Cambridge International IGCSE Chemistry (0620) — 6.4 Redox · Explain · 4 marks

> Zinc powder is added to copper(II) sulfate solution. The blue colour of the solution fades and a reddish-brown solid forms.

## Mark scheme (4 marks)

1. Zinc loses electrons / is oxidised
2. Oxidation state of zinc increases from 0 to +2
3. Copper(II) ions gain electrons / are reduced
4. Oxidation state of copper decreases from +2 to 0

## Key terms

- [redox](https://www.gradenine.co.uk/glossary/redox)
- [oxidation](https://www.gradenine.co.uk/glossary/oxidation)
- [oxidation state](https://www.gradenine.co.uk/glossary/oxidation-state)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](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/zinc-powder-is-added-to-copper-ii-1564d3df) · Published by Druglandscape Ltd.