Acyl chlorides and estersEdexcel A-Level Chemistry: Subtopic test

1. 1
   Ethanoyl chloride, CH₃COCl, is a colourless liquid that fumes in moist air. A technician adds it carefully to several different reagents in a fume cupboard.

   (a)

   What is seen when a few drops of ethanoyl chloride are added to water?

   [1 mark]

   • ANo visible change
   • BSteamy white fumes of hydrogen chloride
   • CAn orange precipitate
   • DA silver mirror on the container

   (b)

   Which organic product forms when ethanoyl chloride reacts with an excess of concentrated ammonia?

   [1 mark]

   • AEthanamide
   • BEthylamine
   • CAmmonium ethanoate
   • DEthanenitrile

   (c)

   Ethanoyl chloride reacts with ethylamine. Name the organic product and write the equation for the reaction.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Ethyl propanoate, CH₃CH₂COOCH₂CH₃, is hydrolysed in two separate experiments. In the first it is heated under reflux with dilute sulfuric acid. In the second it is heated under reflux with aqueous sodium hydroxide.

   (a)

   What are the products of the reaction with aqueous sodium hydroxide?

   [1 mark]

   • APropanoic acid and ethanol
   • BEthanoic acid and propan-1-ol
   • CSodium ethanoate and propan-1-ol
   • DSodium propanoate and ethanol

   (b)

   Which statement about the two hydrolysis reactions is correct?

   [1 mark]

   • AAcid hydrolysis goes to completion
   • BAlkaline hydrolysis is reversible
   • CAlkaline hydrolysis is not reversible because the carboxylate ion is not attacked by the alcohol
   • DAcid hydrolysis forms a sodium salt

   (c)

   Describe how propanoic acid can be obtained from the mixture formed after alkaline hydrolysis, and write an ionic equation for the reaction involved.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A flavour company makes propyl ethanoate, which has a pear-like smell. It can be made from propan-1-ol using either ethanoic acid or ethanoyl chloride. The company also tests samples of the ester by hydrolysing them.

   (a)

   Give the conditions for the acid hydrolysis of propyl ethanoate and name the two organic products.

   [3 marks]

   (b)

   Compare the preparation of propyl ethanoate from ethanoic acid with its preparation from ethanoyl chloride.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A teaching technician demonstrates the reactivity of ethanoyl chloride, then asks students to hydrolyse the ethyl ethanoate they have made so that the products can be isolated.

   (a)

   Describe the reactions of ethanoyl chloride with water, ethanol, concentrated ammonia and ethylamine, giving the organic products and what is seen.

   [6 marks]

   (b)

   Compare acid and alkaline hydrolysis of ethyl ethanoate, and justify which method should be used to obtain the greatest yield of ethanoic acid.

   [6 marks]

   Total for question 4: 12 marks

End of questions