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Nuclear magnetic resonance spectroscopy (A-level only)

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Question 2

Compounds A, B, C and D are isomers with the molecular formula C7H14O2\text{C}_7\text{H}_{14}\text{O}_2C7​H14​O2​.

Isomers A and B are carboxylic acids with formulas that can be written as C6H13COOH\text{C}_6\text{H}_{13}\text{COOH}C6​H13​COOH.

a.

Give an equation for the reaction of C6H13COOH\text{C}_6\text{H}_{13}\text{COOH}C6​H13​COOH with sodium carbonate.

[1]
b.

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

[1]
c.

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

[2]
d.

Isomer C has three singlets with integration ratio 3:2:93:2:93:2:9 in its 1H{}^1\text{H}1H NMR spectrum. Deduce the structure of C 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 D:

Chemical shift δ\deltaδ / ppmIntegration ratioSplitting pattern
4.122quartet
1.253triplet
1.159singlet
  • 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.
[5]

Nuclear magnetic resonance spectroscopy (A-level only) Questions

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