The correct statement regarding the comparison of staggered and eclipsed conformations of ethane is:
Answer: (D) The staggered conformation of ethane is more stable than the eclipsed conformation, because the staggered conformation has no torsional strain.. \textbf{Answer:} (d) staggered is more stable (no torsional strain) \textbf{Solution:} In the staggered conformation of ethane the bonds on the two carbons are apart (dihedral angle), minimising electron-pair repulsion, so it has no torsional strain and is the most stable conformer.
- A.The staggered conformation of ethane is less stable than the eclipsed conformation, because the staggered conformation has torsional strain.
- B.The eclipsed conformation of ethane is more stable than the staggered conformation, because the eclipsed conformation has no torsional strain.
- C.The eclipsed conformation of ethane is more stable than the staggered conformation even though the eclipsed conformation has torsional strain.
- D.The staggered conformation of ethane is more stable than the eclipsed conformation, because the staggered conformation has no torsional strain.✓
Correct Answer
(D) The staggered conformation of ethane is more stable than the eclipsed conformation, because the staggered conformation has no torsional strain.
Solution & Explanation
\textbf{Answer:} (d) staggered is more stable (no torsional strain) \textbf{Solution:} In the staggered conformation of ethane the bonds on the two carbons are apart (dihedral angle), minimising electron-pair repulsion, so it has no torsional strain and is the most stable conformer. The eclipsed conformation has bonds aligned ( dihedral), giving maximum torsional strain and the highest energy. Therefore the staggered conformer is more stable because it is free of torsional strain. Hence (d).