# Chloroethane can be converted into ethanol by reacting it with aqueous sodium hydroxide. This is an example of a substitution reaction involving a halogenoalkane. Explain why halogenoalkanes are reactive and describe what happens during this substitution reaction.

> WJEC A-Level Chemistry (Wales) — 2.6 Halogenoalkanes · Explain · 5 marks

> Chloroethane has the molecular formula C₂H₅Cl. It reacts with aqueous sodium hydroxide solution to produce ethanol and sodium chloride.

## Mark scheme (5 marks)

1. The carbon–halogen bond is polar / the C–Cl bond is polar
2. Chlorine is more electronegative than carbon, so it carries a partial negative charge (δ−) and carbon carries a partial positive charge (δ+)
3. The hydroxide ion (OH⁻) acts as a nucleophile and is attracted to the δ+ carbon
4. The hydroxide ion replaces / substitutes the chlorine atom
5. The chlorine leaves as a chloride ion (Cl⁻) and ethanol is formed

## Key terms

- [halogenoalkane](https://www.gradenine.co.uk/glossary/halogenoalkane)
- [substitution reaction](https://www.gradenine.co.uk/glossary/substitution-reaction)

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- [Revision notes for WJEC A-Level Chemistry (Wales)](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/chloroethane-can-be-converted-into-ethanol-3b301187) · Published by Druglandscape Ltd.