# Ethanol belongs to the homologous series called alcohols. Describe four features that define a homologous series and explain why ethanol and propanol both belong to the same homologous series.

> AQA A-Level Chemistry (7405) — 3.3.8 Aldehydes and ketones (A-Level only) · Describe · 5 marks

## Mark scheme (5 marks)

1. A homologous series is a series of compounds with the same functional group
2. Members of a homologous series have similar chemical properties
3. Each successive member differs by CH₂
4. Ethanol and propanol both contain the –OH functional group / are both alcohols
5. Ethanol (C₂H₅OH) and propanol (C₃H₇OH) differ by one CH₂ unit / propanol has one more CH₂ than ethanol

## Key terms

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

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/ethanol-belongs-to-the-homologous-series-c58ebfd2) · Published by Druglandscape Ltd.