| Date | November 2011 | Marks available | 1 | Reference code | 11N.3.hl.TZ0.D4 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Describe | Question number | D4 | Adapted from | N/A |
Question
Chirality plays an important role in the action of drugs.
Using an asterisk (*), identify the chiral carbon atom in the structure of thalidomide.
[1]
a.
Describe the composition of a racemic mixture.
[1]
b.
Markscheme
;
a.
equimolar/50:50 mixture (of a pair) of enantiomers/both isomers;
b.
Examiners report
Identification of the chiral carbon atom was generally well done.
a.
Some were not able to describe the composition of a racemic mixture correctly by not mentioning an equimolar (50:50) mixture.
b.
Syllabus sections
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