# Butane, butene and butanol are organic compounds. State the functional group present in butanol and explain why butane and butanol both belong to different homologous series despite containing the same number of carbon atoms.

> Cambridge International IGCSE Chemistry (0620) — 11.1 Formulae, functional groups and terminology · State and Explain · 4 marks

## Mark scheme (4 marks)

1. The functional group in butanol is the hydroxyl group (–OH)
2. A homologous series is a family/series of compounds with the same functional group (and same general formula)
3. Butane belongs to the alkane homologous series which contains no functional group / has only C–H and C–C single bonds
4. Butanol belongs to the alcohol homologous series because it contains the –OH functional group, which is different from butane's series

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "State and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/butane-butene-and-butanol-are-organic-17e754ad) · Published by Druglandscape Ltd.