# Methanol, ethanol, propanol, and butanol are all members of the alcohol homologous series. Explain what is meant by a homologous series and describe how the physical and chemical properties of alcohols change as the carbon chain length increases.

> Eduqas A-Level Chemistry — 2.7 Alcohols and carboxylic acids · Explain and Describe · 5 marks

## Mark scheme (5 marks)

1. A homologous series is a family/group of compounds with the same general formula / same functional group
2. Each successive member differs by CH₂ (one carbon and two hydrogen atoms)
3. Boiling point increases as carbon chain length increases
4. Solubility in water decreases as carbon chain length increases
5. The chemical reactions / reactions with oxygen (combustion) are the same / similar for all members because they share the same functional group (–OH)

## Key terms

- [homologous series](https://www.gradenine.co.uk/glossary/homologous-series)
- [carbon chain length](https://www.gradenine.co.uk/glossary/carbon-chain-length)

## Related

- [Revision notes for Eduqas A-Level Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Explain and Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/methanol-ethanol-propanol-and-butanol-are-c9fd1024) · Published by Druglandscape Ltd.