# Ethanoic acid is a carboxylic acid. Describe what happens when ethanoic acid reacts with sodium carbonate solution, and explain why ethanoic acid is described as a weak acid.

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

> Ethanoic acid is the carboxylic acid found in vinegar. Its molecular formula is CH₃COOH.

## Mark scheme (5 marks)

1. Ethanoic acid reacts with sodium carbonate to produce a salt (sodium ethanoate)
2. Carbon dioxide gas is produced / effervescence / bubbles observed
3. Water is also produced in the reaction
4. A weak acid only partially / incompletely dissociates / ionises in aqueous solution
5. Unlike a strong acid, ethanoic acid does not completely dissociate, so the concentration of H⁺ ions in solution is lower than for a strong acid of the same concentration

## Key terms

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

## Related

- [Revision notes for WJEC A-Level Chemistry (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/ethanoic-acid-is-a-carboxylic-acid-5901dde9) · Published by Druglandscape Ltd.