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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 · 2025 · Paper II

Q4(a). Primary kinetic isotope effect

Question

Identify which of four displayed reactions has a primary C–H isotope effect: benzene bromination, Claisen rearrangement, acid-catalysed ketone bromination, and alcohol dehydration. [reactions (i)–(iv) given in the paper]

Answer in brief

(iii), acid-catalysed α bromination of the ketone, is the standard clear example.

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Topic notes: methods of studying mechanisms (isotopic labelling, crossover, trapping, kinetic isotope effect, kinetic and thermodynamic control), with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversprimary kinetic isotope effectkH/kDacid-catalysed bromination of ketoneenolisationrate-determining step

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