# Lead(II) oxide can be reduced by heating it with carbon monoxide gas. The equation for this reaction is: PbO + CO → Pb + CO₂. Explain why this reaction is a redox reaction, referring to both oxidation and reduction in your answer.

> Edexcel A-Level Chemistry (9CH0) — 3.1 Oxidation and reduction · Explain · 5 marks

> Lead(II) oxide can be reduced by heating it with carbon monoxide gas. The equation for this reaction is: PbO + CO → Pb + CO₂.

## Mark scheme (5 marks)

1. Reduction is identified as the loss of oxygen
2. Lead(II) oxide / PbO loses oxygen (so lead(II) oxide is reduced)
3. Oxidation is identified as the gain of oxygen
4. Carbon monoxide / CO gains oxygen (so carbon monoxide is oxidised)
5. Both oxidation and reduction occur simultaneously / in the same reaction, so it is a redox reaction

## Key terms

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

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](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)

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