CAIE A Level Chemistry 9701 · Polymerisation
Lactic acid, , is a hydroxycarboxylic acid that can form a polyester. Compare the formation of a polyester from lactic acid with the formation of a polyester from a diol such as ethane-1,2-diol and a dicarboxylic acid such as butanedioic acid. In your answer, refer to the functional groups involved, the linkage formed, and the small molecule eliminated in each case.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
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