Q7 · CSIR-NET Chemistry, June 2013
Paper: CSIR-NET June 2013 · Subject: Organic Chemistry · Chapter: General Organic Chemistry · Topic: Conformational Analysis · Marks: 2 · Difficulty: Medium
Under review — part of this question (a structure or an option) is not clear in the source scan. 4AB is checking it against the original book; the answer shown may change.
The most stable conformations of 1, 2-difluoroethane and dl-2, 3-butanediol are 
(a)
and
and(b)
and
and(c)
and
and(d)
Answer
Under review — not yet confirmed.
Answer: D
Explanation
1,2-Difluoroethane prefers the gauche conformer (gauche effect, σ_CH→σ*_CF), and dl-2,3-butanediol places the two OH groups gauche to allow intramolecular hydrogen bonding — pair (d).
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