# Copper wire is placed into a solution of silver nitrate. Over time, the copper wire becomes coated with silver metal and the solution turns blue as copper(II) ions form. Explain why this reaction is a redox reaction.

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

> Copper wire is placed into a solution of silver nitrate. Over time, the copper wire becomes coated with silver metal and the solution turns blue as copper(II) ions form.

## Mark scheme (4 marks)

1. Copper atoms lose electrons / copper is oxidised
2. Copper atoms form copper(II) ions / Cu → Cu²⁺
3. Silver ions gain electrons / silver ions are reduced
4. Both oxidation and reduction occur simultaneously / electrons are transferred from copper to silver ions

## Key terms

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

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