Question

Which of the following conformations of butane has the lowest energy?

• A. anti
• B. gauche
• C. eclipsed
• D. staggered

Answer 1

The correct option is A anti

In the anti - conformation of butane (when the dihedral angle = ${180}^0$), the potential energy is at its lowest, therefore it is the most stable. This is due to the methyl groups being farthest away from each other in the molecule.