Comparing the two methods of producing ethanol
4 marks · NormalEthanol can be produced industrially by fermentation or by hydration of ethene.
State the raw material used in fermentation to produce ethanol.
State one condition needed for the hydration of ethene to produce ethanol.
Explain one reason why the production of ethanol by fermentation is considered more sustainable than hydration of ethene.
State one reason why the hydration of ethene is more efficient than fermentation for making ethanol.
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(a) Sugar beet, sugar cane, corn, or other starchy crop
(b) High temperature / high pressure / presence of a catalyst (such as phosphoric acid)
(c) Fermentation uses renewable resources / plants can be regrown
(d) Hydration is a continuous process / faster reaction / higher yield
Common mistakes: Incorrect raw material for fermentation (e.g., ethene).; Condition given for fermentation instead of hydration.
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Marking points
B1 (a) · 1 mark · States correct raw material for fermentation (e.g., sugar beet, sugar cane, corn, starchy material).
B2 (b) · 1 mark · States a correct condition for hydration of ethene (e.g., high temperature, high pressure, catalyst/phosphoric acid).
B3 (c) · 1 mark · Explains why fermentation is more sustainable (uses renewable resources).
B4 (d) · 1 mark · States reason hydration is more efficient (e.g., faster, continuous process, higher yield).
Worked solution
a. The raw material for fermentation is sugar (from sugar beet, sugar cane, corn, or other starchy materials).
b. Hydration of ethene uses high temperature, high pressure, or a phosphoric acid catalyst.
c. Fermentation is considered more sustainable because it uses renewable resources—plants can be regrown.
d. Hydration of ethene is more efficient because it is a continuous process and the reaction is faster.