1. 1
   A perfume manufacturer uses a compound with a fruity smell as a flavouring ingredient. This compound belongs to the ester homologous series.

   (a)

   Which functional group is characteristic of an ester?

   [1 mark]

   • A-OH
   • B-COOH
   • C-COO-
   • D>C=C<

   (b)

   Esters such as this one are described as volatile. What does the term 'volatile' mean in this context?

   [1 mark]

   • AThe compound is highly reactive and explosive
   • BThe compound evaporates easily at room temperature
   • CThe compound is highly acidic
   • DThe compound is insoluble in water

   (c)

   Name the ester formed when ethanol and ethanoic acid react together in the presence of an acid catalyst, and state one use of this ester.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A school technician prepares a small sample of ethyl ethanoate by heating ethanol and ethanoic acid together with a few drops of concentrated sulfuric acid.

   (a)

   What is the role of the sulfuric acid in this preparation?

   [1 mark]

   • AIt acts as a catalyst for the esterification reaction
   • BIt acts as the solvent for the reaction
   • CIt supplies the oxygen atoms needed in the ester
   • DIt reacts with the ethanol to form the ester directly

   (b)

   Besides ethyl ethanoate, what other product is formed in this esterification reaction between ethanol and ethanoic acid?

   [1 mark]

   • ACarbon dioxide
   • BHydrogen
   • COxygen
   • DWater

   (c)

   Write a word equation for the reaction between ethanol and ethanoic acid, and describe how the resulting mixture could be distinguished from the starting materials by smell.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A food flavourings company wants to produce a new ester with a different fruity aroma by reacting propan-1-ol with ethanoic acid, rather than using ethanol.

   (a)

   Explain how the identity of the alcohol used affects the name and structure of the resulting ester, referring to propyl ethanoate as the expected product.

   [3 marks]

   (b)

   Given the name propyl ethanoate, describe how the structural formula of this ester could be deduced from the names of the alcohol and carboxylic acid it is formed from.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A cosmetics company plans to manufacture a range of perfumes using different esters, each prepared by reacting a chosen alcohol with a chosen carboxylic acid in the presence of an acid catalyst.

   (a)

   Describe, in general terms, how esters are prepared from alcohols and carboxylic acids, including the conditions required, and explain why esters are particularly suitable for use in perfumes and food flavourings.

   [6 marks]

   (b)

   Evaluate the advantages of using naturally-inspired esters, prepared synthetically in a laboratory, for food flavourings compared with extracting the equivalent natural flavour compounds directly from fruit, considering cost, consistency and scale of production.

   [6 marks]

   Total for question 4: 12 marks

End of questions