The correct structure of benzene was proposed by

Which species is generated during the chlorination of an aromatic ring?

Consider the following sequence of reactions. In $Z$,the number of $sp^3$ carbons is $a$ and $sp^2$ carbons is $b$. The value of $(a+b)$ is:
$CH_3CH_2CH_2CH_2Br$ $\xrightarrow[\text{dry ether}]{Na} X$ $\xrightarrow[\text{10-20 atm}]{\text{Cr}_2\text{O}_3 / 773 \text{ K}} Y$ $\xrightarrow[\text{anhy. AlCl}_3]{\text{CH}_3\text{COCl}} Z$

Which of the following is a non-benzenoid aromatic compound?

Which of the following compounds is not aromatic?

$Benzene$ $\xrightarrow[{{H_2}S{O_4}}]{{HN{O_3}}}(A)$ $\xrightarrow[{FeC{l_3}}]{{C{l_2}}}(B)$
The major product $(B)$ is