At room temperature, the eclipsed and staggered forms of ethane can not be isolated because

Options

A. They interconvert rapidly
B. Both the conformers are equally stable
C. The energy difference between the conformers is large
D. There is a large energy barrier of rotation about the `sigma` bond

Answer

A

Explanation

In staggered and eclipsed conformations of ethane, the basic structure of the ethane molecule and its various bond angles and bond lengths remain same.
Since the repulsion between the non-bonded hydrogen atoms on the two carbons are minimum in the staggered conformation, hence staggered conformation is more stable than the eclipsed conformation by about `12.55 kJ "mol"^(-1)`. Further since this energy barrier of `12.55 kJ "mol"^(-1)` is very small and can be easily met by the collisions of the molecules at room temperature, hence these two conformations of ethane are readily interconvertible and hence cannot be separated at room temperature.