In the given reaction,the product $P$ is

How many $\pi$ electrons are present in naphthalene to decide its aromaticity?

The maximum number of $-NO_2$ groups that can be introduced into benzene by direct nitration is usually

When acetylene is passed through a red hot iron tube,compound $X$ is formed. Which one of the following reactions will yield $X$ as the major product?

Identify the major product of the following reaction:

$A$ and $B$ are isomers. Product $B$ is: (Dewar's Benzene is $A$)