Chemistry - STEREO ISOMERISM Question with Solution | TestHub
Different spatial arrangements of the atoms that result from rotation about a single bond are conformers. n-Butane has four conformers eclipsed, fully eclipsed, gauche and anti. The stability order of these conformers are as follows : Although anti is more stable than gauche but in some cases gauche is more stable than anti. Anti gauche Partial eclipsed Fully eclipsed
Which one of the following is the most stable conformer ?
Options:
Answer:
Solution:
Explanation:
The question asks to identify the most stable conformer among the four given Newman projections of butane-2,3-diol.
Concept:
This question is based on conformational isomerism.
Solution:
All the given options are staggered, indicating low torsional strain. Generally, the anti conformer (groups apart) is the most stable, unless hydrogen bonding stabilizes a gauche form ( apart).
Option (3):
In Option (3), the both OH groups are in a gauche relationship ( dihedral angle). This orientation facilitates stabilizing intramolecular hydrogen bonding between the two OH groups, making it the most stable for 1,2-diols.
Options (1), (2) and (4) lack the alignment of OH groups for hydrogen bonding.
Final Answer: Option (C)