# Propene can be produced by cracking. Explain why propene decolourises bromine water but propane does not.

> AQA GCSE Chemistry (8462) — 4.7.2 Reactions of alkenes and alcohols (Chem only) · Explain · 4 marks

## Mark scheme (4 marks)

1. Propene is unsaturated / has a carbon-carbon double bond
2. The double bond allows propene to react with / add bromine across the double bond
3. Propane is saturated / has no carbon-carbon double bond / has only single bonds
4. Propane cannot react with bromine (water) / propane does not decolourise bromine water because it has no double bond to react with

## Key terms

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

## 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)

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Source: [GradeNine](https://www.gradenine.co.uk/q/propene-can-be-produced-by-cracking-75eb8c45) · Published by Druglandscape Ltd.