CAIE A-Level Chemistry 33.3 Acyl chlorides Question Bank

Practise acyl chloride preparation, reactions, mechanisms and hydrolysis reactivity using equations, structures and curly arrows.

Exam points

complete equations for SOCl2 forming acyl chlorides with HCl and SO2 by-products
draw products from acyl chlorides reacting with alcohols, amines or diols
explain acyl chloride hydrolysis and mechanisms using electron-deficient carbonyl carbon

Covered syllabus points

33.3.1—Preparation of acyl chlorides 33.3.2—Reactions of acyl chlorides 33.3.3—Mechanism: acyl chlorides in reactions 33.3.4—Hydrolysis reactivity: acyl vs alkyl chlorides

[Maximum number: 3]

Benzene can be used to make benzoic acid in the two-step process shown in Fig. 7.1.

Fig. 7.1

When treated with a chlorine-containing reagent under suitable conditions, benzoic acid forms compound L.

When treated with a different chlorine-containing reagent under different conditions, benzoic acid forms compound M.

Suggest and draw structures of compounds L and M in the boxes. The molecular formula of each product is given.

Table for Question 33.3 Acyl chlorides question 1 — CAIE A-Level Chemistry A2

State the reagents and conditions to form compound M from benzoic acid.

Figure for Answer to Question 33.3 Acyl chlorides question 1 — CAIE A-Level Chemistry A2

[1]

M

[1]

$\mathrm{PCl}_{3}$ + heat OR $\mathrm{SOCl}_{2}$ OR $\mathrm{PCl}_{5}$ [1]

[Maximum number: 1]

$\left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{2} \mathrm{NH}$ reacts with ethanoyl chloride, $\mathrm{CH}_{3} \mathrm{COCl}$ .

Complete the equation for this reaction.

$\left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{2} \mathrm{NH}+\mathrm{CH}_{3} \mathrm{COCl} \rightarrow$

$\left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{2} \mathrm{NH}+\mathrm{CH}_{3} \mathrm{COCl} \rightarrow \mathrm{CH}_{3} \mathrm{CON}\left(\mathrm{CH}_{2} \mathrm{CH}_{3}\right)_{2}+\mathrm{HCl}$

[Maximum number: 2]

Benzophenone can also be synthesised in two steps from bromomethylbenzene.

Figure for Question 33.3 Acyl chlorides question 3 — CAIE A-Level Chemistry A2

Name the mechanism of step 3 and suggest reagents and conditions for step 3 .
mechanism of step 3
reagents and conditions

M1 step 3 electrophilic substitution

M2 step 3 benzene and $\mathrm{AlCl}_{3}$ (and heat)

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Covered syllabus points

33.3 Acyl chlorides question 1

33.3 Acyl chlorides question 2

33.3 Acyl chlorides question 3