Question

Increasing order of stability among the three main conformations (Eclipse , Anti, Gauche ) of $2$ - fluoroethanol is:

• A. Eclipse, Gauche, Anti
• B. Gauche, Eclipse, Anti
• C. Eclipse, Anti, Gauche
• D. none of these

Answer 1

The correct option is A Eclipse, Gauche, Anti

Eclipse < Gauche < Anti

In the case of Anti, the two electronegative atoms ($F^{-}andO{H}^{-}$) are oppositely placed and the repulsive forces are minimum making the conformation more stable, whereas in eclipsed the groups are closely placed, thereby showing maximum steric forces, making the conformation less stable.