Question

Which symmetry element makes the given compound achiral?

• A. Plane of symmetry (POS)
• B. Centre of symmetry (COS)
• C. Axis of symmetry (AOS)
• D. Both (a) and (b)

Answer 1

The correct option is D Both (a) and (b)

In order for a molecule to be achiral, it must be superimposable on its mirror image. Molecules with a center of symmetry and/or plane of symmetry meet this criterion.
The given molecule has centre of symmetry for the given figure.
For the given compound has rotation about C-C single bond is also possible, so after rotating one $C$ while another is kept stationary, we get the structure where plane of symmetry passing through middle of the bond to get mirror images.
The plane of symmetry of the molecule is show below:

Hence, (d) is correct.