Question

Which of the following is correct order of stability?

• A. Gauche > Fully Eclipsed > Anti
• B. Anti > Gauche > Fully Eclipsed
• C. Fully Eclipsed > Gauche > Anti
• D. Anti > Fully Eclipsed > Gauche

Answer 1

The correct option is B

Anti > Gauche > Fully Eclipsed

I and VII, II and VI, III and V are same.

Energy vs. Dihedral agle or angle of rotation diagram

Mainly three conformational isomers of butane

Stability order: Staggered > Gauche (Skew) > Eclipsed.

All other infinite possibilities in between staggered and eclipsed conformations are known as skew (Gauche) form.

ðThis is mainly because of Torsional strain.