Question

Which is most appropriate regarding the following two conformers of butane?

• A. I has less torsional strain but more steric strain than II.
• B. I has more torsional strain but less steric strain than II.
• C. I has more torsional as well as steric strain than II.
• D. I and II have equal torsional strain, but II has less steric strain.

Answer 1

The correct option is D I and II have equal torsional strain, but II has less steric strain.

Angles between the bonds are same (same torsional strain) but bulky group are at maximum distance in II (less steric strain).