CAIE A Level Chemistry 9701 · Carbonyl compounds
A student plans to prepare the aldehyde ethanal by oxidising ethanol. The student heats a mixture of ethanol and acidified potassium dichromate(VI) under reflux. Explain why the student will not obtain ethanal as the final organic product, and describe the change to the method needed to obtain ethanal. In your answer, refer to the oxidation states of the carbon in the alcohol, aldehyde and carboxylic acid.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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