# Propene can undergo addition reactions with different reagents. Describe what happens when propene reacts with steam in the presence of an acid catalyst, and explain why this reaction is classified as an addition reaction.

> Cambridge International IGCSE Chemistry (0620) — 11.5 Alkenes · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Propene reacts with steam (water / H₂O) to form propan-1-ol or propan-2-ol (an alcohol)
2. An acid catalyst is required / the reaction requires high temperature and pressure
3. The C=C double bond in propene breaks / opens
4. The atoms of steam / water add across the double bond to form a single bond / one product only is formed with no other products

## Key terms

- [addition reaction](https://www.gradenine.co.uk/glossary/addition-reaction)
- [catalyst](https://www.gradenine.co.uk/glossary/catalyst)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/propene-can-undergo-addition-reactions-with-5a164498) · Published by Druglandscape Ltd.