Question

Which of the following(s) is/are optically active?

• A.
• B.
• C.
• D. Both (a) and (b)

Answer 1

The correct option is B

For a biphenyl to be optically active it should have bulky groups at ortho position and the two group at ortho position of each phenyl ring should be different.

In compound (a), $OH$ group present at ortho positions of same phenyl ring. Hence, they it is optically inactive.

Similarly, compound (c) has not groups at ortho positons. Hence, it is also optically inactive.

Compound (b) has bulky groups at ortho positions and arew different with respect to each phenyl ring. This will restrict the rotation of phenyl rings and shows atropisomerism. Hence, they are optically active.