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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 · 2026 · Paper II, Chemistry · Q93 of 120

Geo-Scientist Prelims 2026 Chemistry Q93: The major products [X] and [Y] formed in the following reaction…

QuestionOrganic / epoxidation and Fürst–Plattner opening

The major products [X] and [Y] formed in the following reaction sequence are

UPSC Combined Geo-Scientist Prelims 2026 Paper II (Chemistry), Q93: figure printed with the question
UPSC Combined Geo-Scientist Prelims 2026 Paper II (Chemistry), Q93: answer options as printed
  1. (a) [X] = α-epoxide (O on the lower face, opposite the angular Me); [Y] = OMe β (wedge) at the carbon next to the ring junction and OH α (hashed) at the adjacent carbon
  2. (b) [X] = β-epoxide (O on the same face as the angular Me); [Y] = OMe β (wedge) next to the ring junction and OH α (hashed) at the adjacent carbon
  3. (c) [X] = α-epoxide; [Y] = OH β (wedge) next to the ring junction and OMe α (hashed) at the adjacent carbon
  4. (d) [X] = β-epoxide; [Y] = OH β (wedge) next to the ring junction and OMe α (hashed) at the adjacent carbon

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