Presence of chiral center is not an essential condition to show optical isomerism. Essential condition is, compound should show non-superimposable mirror image.
Allenes do not contain chiral center but show optical isomerism when different groups are attached on double bonded carbonds.
Biphenyls alos show optical isomerism when both rings are perpendicular to each other and any ring should not contain plane of symmetry.
Which of the following biphenyl compounds is optically active?
A.
B.
C.
D. All are correct
