Benzene and Alkyl Benzene - Result Question 27
####31. Which compound(s) out of the following is/are not aromatic? (2019 Main, 11 Jan I) (a)
(c)
(b)
(d)
(c) (i)
(ii)
(ii)
Show Answer
Solution:
- A compound is considered to be aromatic, if it follows three rules:
(a) Must be cyclic and planar.
(b) Must have conjugated system in it.
(c) It must follow Huckel rule which states that number of $\pi$-electrons $=(4 n+2)$
(A) $\nabla^{\square} \Rightarrow 2 \pi-e^{-} \operatorname{system}[(4 n+2) \pi, n=0] \Rightarrow$ Aromatic
(B) ${ }^{5}$ d) $\Rightarrow 4 \pi-e^{-} \operatorname{system}[4 n \pi, n=1] \Rightarrow$ Anti-aromatic
(C) $\underset{\ominus \odot}{1}$
(D) $\begin{aligned} & \Delta p^{3} \text { The } s p^{3} \text {-carbon does not support conjugation and } \ & \text { also devoids planarity. } \ & \Rightarrow \text { Non-aromatic }\end{aligned}$
