Question

Which of the following statements concerning the conformers of butane is true?

a) The staggered conformation is the most stable.
b) Butane only exists in the eclipsed conformation.
c) Conformers have identical energies.
d) The anti conformation is the least stable.

Answer 1

The true statement concerning the conformers of butane is that the staggered, specifically the anti conformation, is the most stable due to the minimal steric repulsion when the methyl groups are furthest apart.

Step-by-step explanation:

The correct statement concerning the conformers of butane is that the staggered conformation is the most stable. The staggered conformation of butane, particularly the anti conformation, is the most stable because the bulky methyl groups (-CH3) are furthest apart, minimizing steric repulsion and resulting in the lowest potential energy. This conformation is labeled 'A' in the energy versus torsion angle curve. Thus, the true statement among those provided is option (a): The staggered conformation is the most stable. The other options are incorrect: butane does not only exist in the eclipsed conformation, the conformers do not have identical energies, and the anti conformation is not the least stable; instead, it is the most stable configuration for butane.