# Methanol, ethanol, and propanol are all members of the alcohol homologous series. Describe three features that show these substances belong to the same homologous series, and state the functional group present in all alcohols.

> WJEC A-Level Chemistry (Wales) — 2.7 Alcohols and carboxylic acids · Describe · 5 marks

## Mark scheme (5 marks)

1. All alcohols contain the same functional group (–OH / hydroxyl group)
2. Members share the same general formula (CₙH₂ₙ₊₁OH)
3. Each successive member differs by one CH₂ unit / members differ by CH₂
4. Members show a gradual trend / gradual change in physical properties (e.g. boiling point increases with chain length)
5. Members have similar chemical properties / react in the same way

## Key terms

- [homologous series](https://www.gradenine.co.uk/glossary/homologous-series)
- [functional group](https://www.gradenine.co.uk/glossary/functional-group)

## Related

- [Revision notes for WJEC A-Level Chemistry (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "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-and-propanol-are-all-f8078ef0) · Published by Druglandscape Ltd.