Glyoxal is:

Which of the following has the lowest heat of combustion?

The reaction of benzene with $CH_2Cl_2$ in the presence of $AlCl_3$ gives product $A$. Identify $A$.

Which of the following cation/anion is not aromatic?

The reaction of toluene with chlorine in the presence of light gives

What is aromaticity? Explain with suitable examples. State the Huckel rule and explain it with a suitable example. Write the requirements for aromatic character in a compound. Show aromatic structures having $1$,$2$,and $3$ rings with suitable examples.