# Ethanol can be produced by fermentation of sugar solutions using yeast, or by hydration of ethene. Explain why fermentation is considered a more sustainable method of producing ethanol than hydration of ethene. In your answer, refer to the feedstock used in each process.

> AQA A-Level Chemistry (7405) — 3.3.7 Optical isomerism (A-Level only) · Explain · 5 marks

## Mark scheme (5 marks)

1. Fermentation uses sugar / glucose / a renewable / biological feedstock (1 mark)
2. Hydration of ethene uses ethene / a feedstock derived from crude oil (1 mark)
3. Crude oil is a finite / non-renewable resource (1 mark)
4. Sugar / the feedstock for fermentation can be regrown / replaced / is renewable (1 mark)
5. Therefore fermentation is more sustainable because its feedstock will not run out / can be continually replaced (1 mark)

## Key terms

- [fermentation](https://www.gradenine.co.uk/glossary/fermentation)
- [feedstock](https://www.gradenine.co.uk/glossary/feedstock)

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](https://www.gradenine.co.uk/learn)
- [How to answer "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/ethanol-can-be-produced-by-fermentation-800d60bc) · Published by Druglandscape Ltd.