Question

Which of the following are not aromatic?

• A. A, C, E
• B. B , E , F
• C. B , C , F
• D. C, D, E

Answer 1

Answer: (B)

Conditions for species to be an aromatic are:

(i) The aromatic structures follows Huckel's rule, i.e. species have $(4 n+2) \pi$ -electrons in its structure.

where, $n=$ integer $0,1,2,3, \ldots \ldots$ so on.

(ii) Should be planar ring structure.

(A) It follows Huckel's rule and has planar structure thus, is an aromatic $(\because n=1$, $\left.\pi e^{-}=6\right)$

(B) It does not follow Huckel's rule ( $\because$ has $8 \pi$ electrons with $n=2$ ).

(C) It follows Huckel's rule and has planar structure. Thus, is an aromatic $(\because n=1$, $\left.\pi e^{-}=6\right)$

(D) It follows Huckel's rule and has planar structure as it has $n=3$ and $14 \pi$ electrons.

(E) It does not follow Huckel's rule, thus is not an aromatic compound $\left(n=1, \pi e^{-}=4\right)$

(F) It also does not follow Huckel's rule. Thus, is not an aromatic $\left(n=0, \pi e^{-}=4\right)$