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Nuclear magnetic resonance spectroscopy (A-level only)

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Question 4

Compounds A, B, C and D are isomers with the molecular formula C5H10O2\text{C}_5\text{H}_{10}\text{O}_2C5​H10​O2​.

Isomers A and B are carboxylic acids with formulas that can be written as C4H9COOH\text{C}_4\text{H}_9\text{COOH}C4​H9​COOH.

a.

Give an equation for the reaction of C4H9COOH\text{C}_4\text{H}_9\text{COOH}C4​H9​COOH with sodium hydrogencarbonate.

[1]
b.

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

[1]
c.

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

[2]
d.

Isomer C has three singlets with integration ratio 1:3:61:3:61:3:6 in its 1H{}^1\text{H}1H NMR spectrum. Deduce a possible structure of C and explain why the peaks in its 1H{}^1\text{H}1H NMR spectrum are singlets.

[3]
e.

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

Chemical shift δ\deltaδ / ppmIntegration ratioSplitting pattern
8.021singlet
1.489singlet
  • Draw the parts of the structure of D that can be deduced from each of these peaks.
  • Deduce the structure of D.
  • State how many peaks are in the 13C{}^{13}\text{C}13C NMR spectrum of D.
[4]

Nuclear magnetic resonance spectroscopy (A-level only) Questions

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