Comparing the two methods of producing ethanol
2 marks · HardState one reason why ethanol produced by fermentation may need further processing, and one reason why ethanol produced by hydration of ethene is considered more efficient.
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Also accept: Fermentation produces impure ethanol / Hydration produces very pure ethanol; Batch process is inefficient / Hydration is a continuous process and so is more efficient; Fermentation is slow / Hydration is faster
Common mistakes: Saying fermentation is more efficient than hydration; Confusing purity of ethanol between the two methods
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Marking points
B1 · 1 mark · One correct reason why fermentation ethanol requires further processing (e.g. impure)
B2 · 1 mark · One correct reason why hydration is considered more efficient than fermentation
Worked solution
Ethanol produced by fermentation is very impure so it needs to be purified before use. Hydration of ethene is considered more efficient because it is a continuous process and produces ethanol much faster.