Compound Q can be synthesised from chlorobenzene in seven steps, using the route shown in Fig. 5.1. [Figure 5.1, showing a seven-step reaction scheme starting from chlorobenzene to compound Q]

1. (a)(i)Write an equation for the formation of the electrophile for step 1.[1]
2. (a)(ii)Complete the mechanism in Fig. 5.2 for step 1, the alkylation of chlorobenzene. Include all relevant curly arrows and charges. Draw the structure of the intermediate. [Figure 5.2, partial mechanism starting from chlorobenzene, showing intermediate box and final product with H+][3]
3. (a)(iii)Step 2 is an oxidation reaction. Construct an equation for the reaction in step 2. Use [O] to represent an atom of oxygen from an oxidising agent.[1]
4. (a)(iv)Suggest reagents for the conversion of K to M in steps 3 and 4. step 3 step 4[2]
5. (a)(v)Identify the type of reaction that occurs in step 5.[1]
6. (a)(vi)Step 7 takes place when P is heated with a weak base such as K2CO3(aq). [Figure showing reaction of P with HN to form Q] Suggest why a strong base such as NaOH(aq) is not used for this reaction.[1]
7. (a)(vii)Q is optically active. Explain the meaning of optically active.[1]
8. (a)(viii)Give two reasons why it might be desirable to synthesise a single optical isomer of Q for use as a drug. 1 2[2]
9. (b)Q is commonly used in conjunction with aspirin. aspirin [Figure showing structure of aspirin] Aspirin is a weak Brønsted-Lowry acid.
10. (b)(i)The pKa of aspirin is 3.49. 75mg of aspirin dissolves in water to form 100cm³ of an aqueous solution. Calculate the pH of this solution. [Mr: aspirin, 180.0] pH =[3]
11. (b)(ii)Aspirin undergoes acid hydrolysis in the stomach. Give the structures of the organic products of this acid hydrolysis.[2]

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