Ethanol can be oxidised by heating with potassium dichromate(VI) in dilute sulfuric acid
3 marks · NormalEthanol is sometimes used to make vinegar by oxidation. Explain, in terms of the laboratory process, how a chemist could use potassium dichromate(VI) and dilute sulfuric acid to produce ethanoic acid from ethanol.
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The chemist heats ethanol with potassium dichromate(VI) and dilute sulfuric acid. Ethanol is oxidised to ethanoic acid; the potassium dichromate changes from orange to green as it is reduced.
Also accept: Heat ethanol with acidified potassium dichromate; ethanol is converted to ethanoic acid.
Common mistakes: Does not specify heating.; Does not mention acidified oxidising agent.
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Marking points
M1 · 1 mark · Describes heating ethanol with potassium dichromate(VI) and dilute sulfuric acid.
M2 · 1 mark · States ethanol is oxidised to ethanoic acid (or acetic acid).
A1 · 1 mark · Mentions the orange to green colour change as evidence of the reaction.
Worked solution
To produce ethanoic acid from ethanol in the lab, a chemist would heat ethanol with a mixture of potassium dichromate(VI) and dilute sulfuric acid. The ethanol is oxidised to ethanoic acid. The solution changes colour from orange to green as the potassium dichromate(VI) is reduced.