Question

Identify the polynuclear aromatic compound which is aromatic.

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (i), (ii) and (iii)
• D. (i) and (iii)

Answer 1

Answer: (C)

(i), (ii) and (iii)

For any compound to be aromatic, all carbon atoms must be $s{p}^2$ hybridised and must follow Huckle rule.

Huckel's Rule $\Rightarrow$ $4n+2=$ no. of delocalised $\pi$-electrons ($n=0,1,2,\mathrm{3...}$)

(i) $4n+2=10$ $\Rightarrow$ $n=2$

(ii) $4n+2=14$ $\Rightarrow$ $n=3$

(iii) $4n+2=14$ $\Rightarrow$ $n=3$

All compounds follow Huckel's rule, thus all are aromatic compounds.

Hence, the correct answer is option $\text{C}$.