CAIE A Level Chemistry 9701 · Carboxylic acids and derivatives

Carboxylic acids and derivatives: compare question

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A student investigates the rates of hydrolysis of three compounds when added to water at room temperature.

Compound A: ethanoyl chloride, $\ce{CH3COCl}$
Compound B: chloroethane, $\ce{C2H5Cl}$
Compound C: chlorobenzene, $\ce{C6H5Cl}$

The student observes that compound A reacts instantly with water, producing fumes of hydrogen chloride. Compound B reacts very slowly, with a small amount of hydrogen chloride detected after several hours. Compound C shows no measurable reaction even after several days.

Compare the ease of hydrolysis of acyl chlorides, alkyl chlorides and halogenoarenes. Explain the differences in terms of the mechanisms involved and the stability of any intermediates.

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5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.

Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.

Carboxylic acids and derivatives: compare question

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