UPSC Civil Services (Mains), Chemistry optional · 2024 · Paper II
Q8(c)(ii). Fragmentation of diethyl ether
Question
The mass spectral data of diethyl ether are: m/z 74, 59, 45, 31, 29. Explain the fragmentation pattern.
Answer in brief
74 is M⁺·; 59 comes from α-cleavage (loss of ·CH₃) and 31 from 59 by loss of ethene; 45 is CH₃CH=OH⁺; 29 is the ethyl cation.
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Coversmass spectrometrydiethyl etherα-cleavageoxonium ionfragmentation pattern
All parts of Question 8
- 8(a) Assignment of four C=O stretching bands15 marks
- 8(b)(i) Ring opening of 2,2-dimethylcyclopropanone by methoxide10 marks
- 8(b)(ii) Order of J(Ha–Hb)5 marks
- 8(c)(i) Two alkenes from 2-chloro-2,3-dimethylbutane10 marks
- 8(c)(ii) Fragmentation of diethyl ether5 marks
- 8(c)(iii) Bond length of HCl from its moment of inertia5 marks