DP Chemistry (last assessment 2024)

Question 20N.3.sl.TZ0.11c

Date	November 2020	Marks available	[Maximum mark: 1]	Reference code	20N.3.sl.TZ0.11c
Level	sl	Paper	3	Time zone	TZ0
Command term	Draw	Question number	c	Adapted from	N/A

[Maximum mark: 1]

20N.3.sl.TZ0.11c

Aspirin is formed by reacting salicylic acid with ethanoic anhydride. The structure of aspirin is given in section 37 of the data booklet.

(c)

The solubility of aspirin is increased by converting it to an ionic form. Draw the structure of the ionic form of aspirin.

[1]

Markscheme

✔

Accept a positive metal ion next to the $C O O^{-}$ such as “ $N a^{+} / K^{+}$ ”.

Accept “ $- O N a / - O K$ ” without showing the charges.

Accept notations such as “ $R C O O^{-}$ ” OR “ $R C O O N a$ ” OR “ $R C O O K$ ” but not “ $R O^{-}$ ” OR “ $R O N a$ ” OR “ $R O K$ ”.

Examiners report

Not well answered. Students evidenced familiarity with the content but failed to provide correct structures. Showing lines used to represent covalent bonds to show an ionic interaction, using convention for complexes, showing only one ion were some of the many mistakes. Many students also had an incorrect product having the aspirin lose the -OH group from the carboxylic acid or the entire carboxylic acid functional group rather than just the H⁺.

Syllabus sections

Options

Options » D: Medicinal chemistry » D.2 Aspirin and penicillin

Options » D: Medicinal chemistry

Question 20N.3.sl.TZ0.11c

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