Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. A-level CHEMISTRY Paper 3 2 *02* IB/M/Jun24/7405/3 Do not write outside the Section A box Answer all questions in this section. 0 1 The structure of 2-hydroxybenzenecarboxylic acid is shown. 0 1 . 1 Give the equation for the reaction of 2-hydroxybenzenecarboxylic acid with methanol. In your equation, include the skeletal formula of the organic product. [2 marks] Aspirin is produced from 2-hydroxybenzenecarboxylic acid by reaction with ethanoic anhydride in the presence of concentrated phosphoric acid. Method 1. Add 2-hydroxybenzenecarboxylic acid to a conical flask. 2. Add excess ethanoic anhydride. 3. Add a few drops of concentrated phosphoric acid. 4. Heat the flask to 85 °C for 10 minutes. 5. Cool the flask and pour the contents into 150 cm3 of cold water. 6. Filter and wash the impure solid aspirin. 7. Recrystallise the aspirin using a 50:50 mixture of water and ethanol. 8. Check the purity of the aspirin. 0 1 . 2 Aspirin can also be produced by reacting 2-hydroxybenzenecarboxylic acid with ethanoyl chloride. State why ethanoic anhydride is preferred to ethanoyl chloride for this preparation. [1 mark] 3 *03* Turn over ► IB/M/Jun24/7405/3 Do not write outside the 0 1 box . 3 Give the name of the mechanism for the reaction of 2-hydroxybenzenecarboxylic acid with ethanoic anhydride. [1 mark] 0 1 . 4 Suggest the role of the concentrated phosphoric acid. [1 mark] 0 1 . 5 Suggest why reflux is not essential when the flask is heated to 85 °C for 10 minutes. [1 mark] 0 1 . 6 Complete and label the diagram to show how the impure solid is filtered. [2 marks] Question 1 continues on the next page 4 *04* IB/M/Jun24/7405/3 Do not write outside the box 0 1 . 7 Suggest the identity of two impurities present in the filtered solid aspirin before it is washed in Step 6 of the method. [2 marks] Impurity 1 Impurity 2 0 1 . 8 Describe the recrystallisation process used to purify the aspirin. Include the method and apparatus used. [6 marks]