Question

The correct statement regarding the comparison of
staggered and eclipsed conformation of ethane, is [2016]
(a) The staggered conformation of ethane is less stable
than eclipsed conformation, because staggered
conformation has torsional strain
(b) The eclipsed conformation of ethane is more stable
than staggered conformation, because eclipsed
conformation has no torsional strain
(c) The eclipsed conformation of ethane is more stable
than staggered conformation even though the eclipsed
conformation has torsional strain
(d) The staggered conformation of ethane is more stable
than eclipsed conformation, because staggered
conformation has no torsional strain.

Answer 1

The correct answer about comparison of the eclipsed and staggered ethane conformation is that, it does not have any torslonal pressure to the eclipsed conformation.

• The staggered ethane conformation is more stable than overshadowed conformation. Because eclipsed conformation has greater energy potential due to torsional strain, it is less stable than staggered conformation.
• Staggered conformations are more stable than eclipsed conformations because a C-H bond bisecting an H-C-H bond at the adjacent C (60°) distances the C-H bonds.
• Eclipsed conformation aligns the C-H bonds, forcing the atoms too close together and thereby creating steric strain and torsional strain.