# Trimethylamine, (CH₃)₃N, is an amine found in decaying fish. When trimethylamine dissolves in water, the solution formed turns red litmus paper blue. Explain why the solution formed is alkaline, and state what type of reaction occurs when trimethylamine reacts with hydrochloric acid.

> Eduqas A-Level Chemistry — 4.6 Amines · Explain · 5 marks

> Trimethylamine, (CH₃)₃N, is an amine responsible for the smell of rotting fish. It is a colourless gas at room temperature that dissolves readily in water.

## Mark scheme (5 marks)

1. Amines contain a nitrogen atom with a lone pair of electrons
2. The lone pair accepts a proton (H⁺) from water
3. This produces hydroxide ions (OH⁻) in solution
4. Hydroxide ions (OH⁻) in excess make the solution alkaline
5. The reaction between trimethylamine and hydrochloric acid is a neutralisation reaction

## Key terms

- [amine](https://www.gradenine.co.uk/glossary/amine)
- [alkaline](https://www.gradenine.co.uk/glossary/alkaline)

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Source: [GradeNine](https://www.gradenine.co.uk/q/trimethylamine-ch-n-is-an-amine-found-d66664c1) · Published by Druglandscape Ltd.