CAIE A Level Chemistry 9701 · Analytical techniques
The carbon-13 NMR spectrum of an unknown compound A, with molecular formula , consists of four peaks. The carbon-13 NMR spectrum of an isomer of A, compound B, also with molecular formula , consists of only two peaks.
Compare the carbon-13 NMR spectra of A and B, and deduce the structures of A and B. Explain the difference in the number of peaks observed.
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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