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CAIE A-Level Chemistry 37.4.2 Proton NMR Shifts and Splitting

Practise predicting proton chemical-shift ranges and splitting patterns directly from a molecular structure.

Syllabus
2028–2030
Course
Chemistry 9701
Level
A2

Exam points

  • assign each proton environment a δ range from its bonding context and the supplied data table
  • count equivalent hydrogens on adjacent carbon atoms and apply n+1 to predict the splitting pattern
  • treat chemically equivalent neighbouring protons correctly and check predicted signals against molecular symmetry

37.4.2—The chemical shifts and splitting patterns question 1

[Maximum number: 1]

D and E are both esters with the molecular formula C5H10O2\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}. Their proton (1H)NMR\left({ }^{1} \mathrm{H}\right) \mathrm{NMR} spectra are shown in Fig. 9.2 and Fig. 9.3.

Fig. 9.2

Fig. 9.2

Fig. 9.3

Fig. 9.3

Table 9.2

Table 9.2

The spectrum of E has a doublet at δ\delta 1.1.

Identify the protons responsible for this doublet on your structure in (i) by labelling these protons with the letter G.

Explain why this peak has a chemical shift of 1.1.

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