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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 · 2024 · Paper II

Q5(g). Chlorine and bromine isotope patterns

Question

How do isotope-peak intensities identify chlorine, bromine, or both in a molecule?

Answer in brief

One Cl gives M:M+2 about 3:1; one Br gives about 1:1; one Cl plus one Br gives M:M+2:M+4 about 3:4:1.

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Topic notes: mass spectrometry: molecular ion, metastable peak and McLafferty rearrangement, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversmass spectrometry isotope patternM+2 peakchlorine bromine isotopesM+4 peakhalogen identification

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