Ethanol can be oxidised by heating with potassium dichromate(VI) in dilute sulfuric acid
3 marks · EasyExplain why dilute sulfuric acid must be present for potassium dichromate(VI) to oxidise ethanol.
State the role of sulfuric acid in this reaction.
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(a) Sulfuric acid provides the hydrogen ions needed for potassium dichromate(VI) to act as an oxidising agent and allow the redox reaction to occur. · must show provides H+ ions or acid conditions, necessary for oxidising agent to work
(b) Provides H+ ions (or maintains acidic conditions). · must show Provides H+ ions or keeps solution acidic
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Marking points
M1 (a) · 1 mark · Mentions that sulfuric acid provides hydrogen ions (or keeps acidic conditions).
M2 (a) · 1 mark · Mentions that these ions are required for potassium dichromate(VI) to function as an oxidising agent/redox reaction to occur.
B1 (b) · 1 mark · States that sulfuric acid provides hydrogen ions (H+) or keeps the solution acidic.
Worked solution
a) Sulfuric acid must be present because it provides the hydrogen ions needed for the potassium dichromate(VI) to act as an oxidising agent. Without these ions, the redox reaction cannot take place.
b) It provides H+ ions.