Deduce the number of peaks in the \(^{\text{1}}{\text{H}}\,{\text{NMR}}\) spectra of 1-bromobutane and 2-bromobutane. Explain how the integration trace can be used to distinguish between the two compounds.

Compare the \(^{\text{1}}{\text{H}}\,{\text{NMR}}\) spectrum of 1-bromo-2-methylpropane with the two spectra considered in (a). Include the number of peaks and the integration trace.

both 1-bromobutane and 2-bromobutane have four peaks;

(ratio of areas in) 1-bromobutane: 3:2:2:2;

(ratio of areas in) 2-bromobutane: 3:1:2:3;

For second and third points accept correct ratios given in a different order.

Accept correct number of hydrogen atoms for each peak instead of area.

three peaks (not four);

ratio of areas/integration trace: 6:1:2;

Accept correct ratio given in a different order.

This is a topic that showed better understanding, but many candidates lost marks as their answers did not focus on integration traces. Thus, it looks like quite a few candidates are actually proficient in this technique, but failed to interpret the question properly. Very few candidates could explain the role of \(^{\text{1}}{\text{H}}\,{\text{NMR}}\) in magnetic resonance imaging. Explanations were very shallow evidencing no clear understanding of this technique.

This is a topic that showed better understanding, but many candidates lost marks as their answers did not focus on integration traces. Thus, it looks like quite a few candidates are actually proficient in this technique, but failed to interpret the question properly. Very few candidates could explain the role of \(^{\text{1}}{\text{H}}\,{\text{NMR}}\) in magnetic resonance imaging. Explanations were very shallow evidencing no clear understanding of this technique.