Answer :
Final answer:
The most stable conformation of ethane is the staggered conformation, while conformers with significant torsional and steric strain are less stable. The staggered conformation minimizes electrostatic repulsion between electron clouds in bonds, which provides stability.
Explanation:
The question asks which conformation among torsional strain, steric strain, or ethane is the most stable or least stable. To discuss stability among conformers, we usually examine the rotational conformations of ethane, as it serves as a simple model for understanding these concepts.
Most Stable Conformation of Ethane
The most stable rotational conformation of ethane is the staggered conformation. In the staggered conformation of ethane, all the C-H bonds on one carbon are positioned at a 60° dihedral angle relative to the C-H bonds on the adjacent carbon. This maximizes the distance between the electron clouds in the bonds, which minimizes electrostatic repulsion and makes the staggered conformation energetically favored. No steric strain or torsional strain is present in the staggered conformation of ethane. On the other hand, the eclipsed conformation of ethane, where the bonds are aligned with each other, is less stable due to increased repulsion.
Least Stable Conformation
In general, the most strained conformer is one with the most steric strain and torsional strain. For example, in 2,3-dimethylbutane, the conformation with two CH3-CH3 torsional interactions would be the least stable due to the significant steric hindrance.
