AQA A LEVEL CHEMISTRY PAPER 3 (7405/3) QP MERGED WITH MARK SCHEME JUNE 2024
A-level
CHEMISTRY
Paper 3
Friday 21 June 2024 Morning Time allowed: 2 hours
For Examiner’s Use
Question Mark
1
2
3
4
5
Section B
TOTAL
AQA QP + MARK SCHEME
IB/M/Jun24/G4006/E8 7405/3
, 2
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]
IB/M/Jun24/7405/3
, 3
Do not write
outside the
0 1 . 3 Give the name of the mechanism for the reaction of box
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
Turn over ►
IB/M/Jun24/7405/3
, 4
Do not write
outside the
0 1 . 7 Suggest the identity of two impurities present in the filtered solid aspirin before it is box
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]
IB/M/Jun24/7405/3
A-level
CHEMISTRY
Paper 3
Friday 21 June 2024 Morning Time allowed: 2 hours
For Examiner’s Use
Question Mark
1
2
3
4
5
Section B
TOTAL
AQA QP + MARK SCHEME
IB/M/Jun24/G4006/E8 7405/3
, 2
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]
IB/M/Jun24/7405/3
, 3
Do not write
outside the
0 1 . 3 Give the name of the mechanism for the reaction of box
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
Turn over ►
IB/M/Jun24/7405/3
, 4
Do not write
outside the
0 1 . 7 Suggest the identity of two impurities present in the filtered solid aspirin before it is box
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]
IB/M/Jun24/7405/3
