Ethene can be converted into ethanol by two different methods: hydration with steam, and fermentation. Compare these two methods in terms of the conditions required and the type of process involved.

Hydration of ethene:
1. Requires high temperature and pressure (≈200 °C, 10–20 bar) and a catalyst (phosphoric acid).
2. Is carried out as a continuous process.
3. Gives ethanol directly, so the product is relatively pure.

Fermentation of ethene (via glucose):
1. Takes place at moderate or room temperature (≈25 °C) and atmospheric pressure.
2. Uses yeast (an enzyme system) as the catalyst.
3. Is a batch process.
4. Produces a dilute ethanol solution that must be concentrated by distillation.

Comparison: Hydration needs harsh conditions, a chemical catalyst and runs continuously, yielding pure ethanol; fermentation uses mild conditions, a biological catalyst, runs in batches and produces a dilute product that must be distilled.