# Hydrocarbons can be described as either saturated or unsaturated. Explain the difference between saturated and unsaturated hydrocarbons, and describe the chemical test that can be used to distinguish between them, including the results you would observe for each type.

> Eduqas A-Level Chemistry — 2.5 Hydrocarbons · Explain · 5 marks

## Mark scheme (5 marks)

1. Saturated hydrocarbons contain only single (C–C) bonds between carbon atoms
2. Unsaturated hydrocarbons contain at least one carbon-carbon double bond (C=C)
3. Bromine water is added to test for saturation / unsaturation
4. Unsaturated hydrocarbon decolourises / turns bromine water from orange/brown to colourless
5. Saturated hydrocarbon does not decolourise bromine water / bromine water stays orange/brown

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/hydrocarbons-can-be-described-as-either-adc02da4) · Published by Druglandscape Ltd.