The structure of 4-ethoxyaniline (also known as p-phenetidine) is shown below:
a.[2]
Give the chemical equation for the reaction of 4-ethoxyaniline with ethanoic anhydride to form the analgesic drug phenacetin. In your equation, use the skeletal formula for the organic product phenacetin.
b.[3]
Phenacetin can also be prepared by reacting 4-ethoxyaniline with ethanoyl chloride. Explain why ethanoic anhydride is chosen in preference to ethanoyl chloride in industrial and laboratory preparations.
c.[3]
State the physical property that is measured to check the purity of the phenacetin crystals. State two ways in which the measurement would indicate that the product contains impurities.