# Butanoic acid is a carboxylic acid. A student adds an excess of sodium carbonate powder to a sample of butanoic acid solution. Describe what the student would observe, name the type of reaction occurring, and state the name of one gas produced.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 4.6 Carboxylic acids · Describe · 4 marks

> Butanoic acid has the molecular formula C₃H₇COOH and is the fourth member of the carboxylic acids homologous series. Like all carboxylic acids, it displays typical acidic properties.

## Mark scheme (4 marks)

1. Effervescence / bubbles are observed (accept: fizzing)
2. The sodium carbonate (solid) dissolves / disappears (accept: the powder dissolves into the solution)
3. The type of reaction is a neutralisation reaction (accept: acid–base reaction)
4. The gas produced is carbon dioxide (accept: CO₂)

## Key terms

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

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