Question

Which of the following is not an aromatic compound?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Aromatic compound $\to$ should be cyclic, planar and have delocalization of $\pi$ electrons. They should obey
$(4n+2)\pi e^{-}$ rule.
Compound (a), (c) and (d) has 6 $\pi$ electrons which obey huckel rule and they are aromatic in nature.
Compound (b) has no delocalisation of electrons due to presence of $s{p}^3$ carbon. Hence, it violates huckel rule and it is a non-aromatic compound.