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UPSC Combined Geo-Scientist

Chemist

  • 2 objective papers
  • 120 questions each
  • 2 h per paper
  • 100 + 300 marks

Prelims Paper II covers chemistry.

UPSC Combined Geo-Scientist, Prelims · 2020 · Paper II, Chemistry · Q118 of 120

Geo-Scientist Prelims 2020 Chemistry Q118: The major product formed in the following reaction is:

QuestionOrganic / Wagner–Meerwein rearrangement

The major product formed in the following reaction is:

UPSC Combined Geo-Scientist Prelims 2020 Paper II (Chemistry), Q118: figure printed with the question
UPSC Combined Geo-Scientist Prelims 2020 Paper II (Chemistry), Q118: answer options as printed
  1. (a) 2,3-Dimethylnorborn-2-ene
  2. (b) 5,5-Dimethylnorborn-2-ene
  3. (c) Dimethylnorbornene isomer as drawn (C=C away from the gem position)
  4. (d) 3,3-Dimethylnorbornan-2-one

Answer: (a)

Protonation and loss of water at C2 next to the gem-dimethyl carbon → 1,2-methyl shift gives a tertiary cation; loss of H⁺ gives the tetrasubstituted alkene 2,3-dimethylnorborn-2-ene → (a).

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