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UPSC Combined Geo-Scientist

Chemist

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

Mains Paper III covers analytical and organic chemistry.

UPSC Combined Geo-Scientist, Mains · 2019 · Mains Paper III

Q7(d). IR activity of alkene stretches

Question

Assess C=C stretching IR activity in 1-octene, 2-methyl-1-heptene, cis-3-hexene and trans-3-hexene.

Answer in brief

The first three are active; the symmetric trans-3-hexene C=C stretch is ideally inactive or very weak.

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The full model answer

As written for the answer booklet: the diagram carries the working, the lines stay short. Read here only; it is not offered as a download.

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CoversIR activity of alkene stretchesVibrational selection rules

All parts of Question 7