Aromatisation of $n$-heptane by passing over $(Al_2O_3 + Cr_2O_3)$ catalyst at $773 \ K$ gives:

Arrange the following in increasing order of reactivity towards nitration:
$A$. $p$-xylene
$B$. bromobenzene
$C$. mesitylene
$D$. nitrobenzene
$E$. benzene
Choose the correct answer from the options given below.

Which of the following is an aromatic compound?

Among the following,the set which represents aromatic species is:

The reaction shown below proceeds through which mechanism?

How many $\pi$-bonds are present in a naphthalene molecule?