# Explain why alkenes react with bromine water but alkanes do not, and describe what you would observe when bromine water is added to an alkene.

> AQA A-Level Chemistry (7405) — 3.3.4 Alkenes · Explain · 5 marks

## Mark scheme (5 marks)

1. Alkenes are unsaturated / contain a carbon-carbon double bond
2. The double bond makes alkenes more reactive than alkanes
3. Alkanes are saturated / contain only single bonds / no double bond
4. Bromine water turns from orange to colourless with an alkene
5. Bromine water remains orange / unchanged with an alkane

## Key terms

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

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](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/explain-why-alkenes-react-with-bromine-d6aa904e) · Published by Druglandscape Ltd.