Final answer:
The correct answer is 'Gauche conformers are more stable than eclipsed.' Anti-conformers are the most stable staggered conformations, while eclipsed conformers experience higher energy and instability due to torsional strain with substituents at a 0° torsion angle.
Step-by-step explanation:
The correct statement about the conformers resulting from rotation about the C₂-C₃ bond of butane is: 'Gauche conformers are more stable than eclipsed.' When analyzing the stability of the conformers of butane, it's essential to consider the relative energy levels. The anti-conformer, shown as A in the Newman projections, is the most stable staggered conformation where the bulky methyl groups are farthest apart. The gauche-conformer, labeled B, is also a staggered conformation, but the methyl groups are at a 60° torsion angle, resulting in some steric repulsion. Despite this, the gauche conformer is still more stable than any of the eclipsed conformers, which correspond to the local energy maxima due to increased torsional strain when substituents on adjacent atoms align with a 0° torsion angle. Specifically, the eclipsed conformer labeled C is less stable by 16 kJ/mol relative to anti-conformer, and the other eclipsed conformation, labeled D, is the least stable with the highest energy.