# Iron can be oxidised and reduced in different chemical reactions. In a thermite reaction, iron(III) oxide reacts with aluminium to produce aluminium oxide and iron metal. Explain what is happening in terms of oxidation and reduction, identifying which substance is oxidised and which is reduced, and explain why aluminium is able to displace iron in this reaction.

> OCR A-Level Chemistry B: Salters (H433) — 2.3 Acid-base and redox reactions · Explain · 5 marks

> The thermite reaction is used industrially to weld railway tracks together. It produces molten iron at very high temperatures. The word equation for the reaction is: iron(III) oxide + aluminium → aluminium oxide + iron.

## Mark scheme (5 marks)

1. Iron(III) oxide is reduced (because iron gains electrons / iron ions gain electrons / oxygen is removed from iron(III) oxide)
2. Aluminium is oxidised (because aluminium loses electrons / oxygen is gained by aluminium)
3. Oxidation and reduction occur simultaneously / this is a redox reaction
4. Aluminium is more reactive than iron (aluminium is higher in the reactivity series than iron)
5. A more reactive metal displaces a less reactive metal from its compound / oxide (so aluminium displaces iron from iron(III) oxide)

## Key terms

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

## Related

- [Revision notes for OCR A-Level Chemistry B: Salters (H433)](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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