Acyl chlorides, esters and polyestersEdexcel International A Level Chemistry: Subtopic test

1. 1
   Ethanoyl chloride, CH₃COCl, is a colourless liquid that fumes in moist air. It is used in the laboratory to make a range of other organic compounds.

   (a)

   What is the name of CH₃CH₂COCl?

   [1 mark]

   • APropyl chloride
   • BPropanoic chloride
   • CPropanoyl chloride
   • DChloropropanone

   (b)

   What are the products when ethanoyl chloride reacts with water?

   [1 mark]

   • AEthanoic acid and hydrogen chloride
   • BEthanol and hydrogen chloride
   • CEthanoic acid and chlorine
   • DEthanal and hydrogen chloride

   (c)

   Write a balanced equation for the reaction of ethanoyl chloride with concentrated ammonia and name the organic product.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Ethyl ethanoate is an ester used as a solvent. A student hydrolyses it by heating under reflux, first with dilute hydrochloric acid and then, in a second experiment, with aqueous sodium hydroxide.

   (a)

   Which pair of compounds forms when ethyl ethanoate is heated under reflux with dilute hydrochloric acid?

   [1 mark]

   • ASodium ethanoate and ethanol
   • BEthanoic acid and ethanol
   • CEthanoic acid and ethanal
   • DEthanoyl chloride and ethanol

   (b)

   Why does the alkaline hydrolysis of the ester go to completion, whereas the acid hydrolysis does not?

   [1 mark]

   • ASodium hydroxide is a stronger catalyst than hydrochloric acid
   • BWater is not needed in alkaline hydrolysis
   • CThe ethanol formed is removed as a gas
   • DThe carboxylic acid is converted into its salt, which cannot react with the alcohol, so the reaction is not reversible

   (c)

   Write the equation for the alkaline hydrolysis of ethyl ethanoate and state what must be added to the product mixture to obtain ethanoic acid.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Propanoyl chloride, CH₃CH₂COCl, is added separately to ethanol, to methylamine, CH₃NH₂, and to concentrated ammonia.

   (a)

   Name the organic product formed in each of the three reactions.

   [3 marks]

   (b)

   Suggest why a chemist might prefer to make ethyl propanoate from propanoyl chloride rather than from propanoic acid, and give one disadvantage of using the acyl chloride.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Terylene is a polyester made by condensation polymerisation of benzene-1,4-dicarboxylic acid, HOOC–C₆H₄–COOH (Mr 166.0), and ethane-1,2-diol, HOCH₂CH₂OH (Mr 62.0). It is used to make clothing fibres and plastic bottles.

   (a)

   Describe how Terylene forms from the two monomers, giving the repeat unit, and explain why it is a condensation polymer and how its ester links can be broken down.

   [6 marks]

   (b)

   Calculate the mass of ethane-1,2-diol and the mass of water formed when 96.0 kg of Terylene is made, assuming a 100% yield and ignoring the end groups of the chains.

   [6 marks]

   Total for question 4: 12 marks

End of questions