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

Which of the following reactions takes place when a mixture of concentrated $HNO_3$ and $H_2SO_4$ reacts with benzene at $350 \ K$?

An aromatic compound,among other things,should have a $\pi$-electron cloud containing $(4n + 2)$ electrons,where $n$ cannot be:

Which of the following are aromatic?

Identify compound $A$ in the following reaction:
$\text{Benzene} + \text{ozone (excess)}$ $\rightarrow \text{Benzenetrizonide}$ $\xrightarrow{A} \text{glyoxal}$

The Friedel-Crafts alkylation of benzene with propene proceeds through the formation of which of the following intermediates?