# Ethanol can be produced by fermentation or by hydration of ethene. Describe the process of fermentation to produce ethanol, and give one advantage of using fermentation rather than hydration of ethene to produce ethanol.

> AQA A-Level Chemistry (7405) — 3.3.5 Alcohols · Describe · 5 marks

> Ethanol is a member of the homologous series of alcohols. It is widely used as a fuel and as a solvent. Two industrial methods exist for its production.

## Mark scheme (5 marks)

1. Sugar (glucose) solution is used as the reactant / starting material
2. Yeast is used as the biological catalyst / yeast carries out the fermentation
3. The process must be carried out in the absence of oxygen / anaerobically
4. Fermentation is carried out at a warm / moderate temperature (approximately 30–40 °C)
5. Fermentation uses a renewable raw material (sugar/glucose from plants) whereas hydration of ethene uses a finite/non-renewable resource (crude oil / ethene from cracking)

## Key terms

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

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](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/ethanol-can-be-produced-by-fermentation-15f0f9c0) · Published by Druglandscape Ltd.