# Propanal and propanone are both organic compounds containing the carbonyl group. Describe how you could use Tollens' reagent to distinguish between propanal and propanone, and explain the observations you would expect for each compound.

> Eduqas A-Level Chemistry — 4.4 Aldehydes and ketones · Describe · 5 marks

## Mark scheme (5 marks)

1. Tollens' reagent contains silver ions / is a solution of silver nitrate in ammonia / is a silver-containing reagent
2. Add Tollens' reagent to each compound and warm gently
3. Propanal (the aldehyde) produces a silver mirror / silver precipitate on the test tube
4. Propanone (the ketone) does not react / no silver mirror / solution remains colourless
5. Propanal is oxidised / acts as a reducing agent; aldehydes can be oxidised but ketones cannot

## Key terms

- [carbonyl group](https://www.gradenine.co.uk/glossary/carbonyl-group)
- [Tollens' reagent](https://www.gradenine.co.uk/glossary/tollens-reagent)

## Related

- [Revision notes for Eduqas A-Level Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/propanal-and-propanone-are-both-organic-b4791bc6) · Published by Druglandscape Ltd.