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Indian Forest Service (Mains)

Chemistry optional

  • 2 papers
  • 200 marks each
  • 3 h per paper

Paper II covers organic chemistry and spectroscopy.

Indian Forest Service (Mains), Chemistry optional · 2016 · Paper II

Q7(b). ¹H NMR of p-xylene and ethylbenzene

Question

How can the NMR spectrum distinguish between the isomers –- p-xylene and ethyl benzene ? Justify your answer.

Answer in brief

p-Xylene: 2 singlets (4H, 6H) ; ethylbenzene: t (3H), q (2H), m (5H) . The number of signals, the ethyl triplet–quartet pattern and the 2: 3 against 5: 2: 3 integrals distinguish them at once.

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