VKC ScienceChemistry for written exams Telegram

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 · 2023 · Mains Paper III

Q7(b). Pentan-1-ol and pentan-2-ol by mass spectrometry

Question

How would you differentiate between the following pairs of alcohols with the help of mass spectrometry? [Structures of pentan-1-ol and pentan-2-ol given in the paper]

Answer in brief

Both give M⁺• at m/z 88 (weak). Pentan-2-ol: base peak m/z 45, and m/z 73. Pentan-1-ol: m/z 31, strong m/z 70 (M − 18) and base peak m/z 42.

Part of VKC Basic

Read the key points and the full model answer with VKC Basic

VKC Basic (₹999 for 6 months) opens every solved answer, the notes, the handbook and the daily answer archive. Every Mains test series includes it.

See what is included Already a member? Sign in

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.

The handwritten model answer pages open with the VKC plan.
Read the whole 2023 solution2023 question paper

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

Coversmass spectrometry of alcoholsα-cleavagepentan-1-olpentan-2-oldehydration peak M-18

All parts of Question 7