Question

Choose the correct statement for the following compounds :

• A. (a) is anti-aromatic.
• B. (b) is anti-aromatic.
• C. (b) is aromatic.
• D. (a) is aromatic.

Answer 1

The correct option is C (b) is aromatic.

In structure (a):
This structure is not planar since one of the carbon is $s{p}^3$ hybridised.
So, (a) is non-aromatic.
In structure (b):
It is cyclic compound.
It is planar, all the carbon atoms are $s{p}^2$ hybridised.
It has $6\pi e^{-}$ i.e. $(4n+2)\pi e^{-}$. It follows huckel's rule.
Resonance is also there.
So, (b) is an aromatic compound.