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Amines (A-level only)

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Question 8

This question is about the preparation of an ester.

Ester GGG can be prepared from ethanol and propanoic acid.

a.

Give a balanced chemical equation for this reaction using condensed structural formulas, and state the IUPAC name of ester GGG.

[2]
b.

The following method is used to prepare a pure sample of ester GGG:

  • Step 1: Mix 12 cm312\text{ cm}^312 cm3 of ethanol with 15 cm315\text{ cm}^315 cm3 of propanoic acid in a reaction flask. Add 555 drops of concentrated sulfuric acid and some anti-bumping granules. Assemble the reflux chemistry apparatus and heat the mixture.
  • Step 2: Transfer the cooled mixture to a separating funnel. Add 20 cm320\text{ cm}^320 cm3 of aqueous sodium carbonate, stopper the funnel, and shake the mixture.
  • Step 3: Run off the organic layer into a beaker, add anhydrous calcium chloride, and decant the liquid.
  • Step 4: Purify the ester using distillation.

Answer the following questions based on this preparation method:

  1. Explain the purpose of adding anti-bumping granules in Step 1.
  2. State the purpose of adding aqueous sodium carbonate in Step 2.
  3. Suggest a precaution (with a reason) that should be taken while shaking the mixture in the separating funnel in Step 2.
  4. State the function of the anhydrous calcium chloride in Step 3.
  5. Suggest how the purity of ester GGG can be confirmed during the distillation in Step 4.
[7]
Markscheme

Amines (A-level only) Questions

  1. A Level
  2. /Chemistry
  3. /Amines (A-level only)

26 exam-style questions on AQA A Level Chemistry Amines (A-level only), covering Preparation (A-level only), Base properties (A-level only), and Nucleophilic properties (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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