# Methanol and butanoic acid can react together to form an ester. Name the ester formed and describe the conditions needed to carry out this reaction in the laboratory. Explain why butanoic acid is described as a weak acid and state one use of esters.

> WJEC A-Level Chemistry (Wales) — 4.5 Carboxylic acids and their derivatives · Describe · 5 marks

## Mark scheme (5 marks)

1. The ester formed is methyl butanoate
2. An acid catalyst is required (concentrated sulfuric acid)
3. The reaction requires heat / is carried out under reflux / mixture is heated
4. Butanoic acid does not fully / completely dissociate (in water) / only partially ionises
5. Esters are used as flavourings / perfumes / solvents

## Key terms

- [ester](https://www.gradenine.co.uk/glossary/ester)
- [weak acid](https://www.gradenine.co.uk/glossary/weak-acid)

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Source: [GradeNine](https://www.gradenine.co.uk/q/methanol-and-butanoic-acid-can-react-c6154851) · Published by Druglandscape Ltd.