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Nuclear magnetic resonance spectroscopy (A-level only)

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Question 5

Compounds V, W, X and Y are isomers with the molecular formula C6H12O2\text{C}_6\text{H}_{12}\text{O}_2C6​H12​O2​.

Isomers V and W are carboxylic acids with formulas that can be written as C5H11COOH\text{C}_5\text{H}_{11}\text{COOH}C5​H11​COOH.

a.

Give an equation for the reaction of C5H11COOH\text{C}_5\text{H}_{11}\text{COOH}C5​H11​COOH with sodium hydrogencarbonate.

[1]
b.

Isomer V has an asymmetric carbon atom. Deduce a possible structure of V.

[1]
c.

Isomer W has four peaks in its 1H{}^1\text{H}1H NMR spectrum. Deduce the structure of W and deduce the integration ratio for its four peaks.

[2]
d.

Isomer X has three singlets with integration ratio 1:2:91:2:91:2:9 in its 1H{}^1\text{H}1H NMR spectrum. Deduce the structure of X and explain why the peaks in its 1H{}^1\text{H}1H NMR spectrum are singlets.

[2]
e.

The table below shows information about the peaks in the 1H{}^1\text{H}1H NMR spectrum of isomer Y:

Chemical shift δ\deltaδ / ppmIntegration ratioSplitting pattern
1.973singlet
1.459singlet
  • Draw the parts of the structure of Y that can be deduced from each of these peaks.
  • Deduce the structure of Y.
  • State how many peaks are in the 13C{}^{13}\text{C}13C NMR spectrum of Y.
[4]

Nuclear magnetic resonance spectroscopy (A-level only) Questions

  1. A Level
  2. /Chemistry
  3. /Nuclear magnetic resonance spectroscopy (A-level only)