Deduce which drugs could be morphine, aspirin and codeine.

Morphine:

Aspirin:

Codeine:

Compare the structures of diamorphine (heroin) and morphine. Their structures are given in table 20 of the data booklet.

Two similarities:

One difference:

Morphine: D;

Aspirin: A;

Codeine: C;

Award [2] for all three correct, [1] for two correct.

Similarities:

Award [1 max] for any two:

benzene ring/aromatic ring/−C₆H₂;

Accept “phenyl” or “arene” but not C₆H₅- or benzene/C₆H₆.

(tertiary) amino/−NRR'/NRR'R'';

Accept “(tertiary) amine”.

carbon−carbon double bond/C=C;

Accept “alkene” or “alkenyl”.

ether/C−O−C;

Accept “both have the same ring structure / OWTTE”.

Difference:

ester/CH₃COO in diamorphine/heroin and hydroxyl/OH in morphine;

Accept “ethanoate” for ester.

Accept “alcohol” or “hydroxy” for hydroxyl but not hydroxide.

Most candidates matched the analgesics to the properties successfully.

Most candidates identified two similarities and one difference between diamorphine and morphine. For the difference, it was necessary to mention both the hydroxyl groups in morphine and the ester groups in diamorphine.