$C-C$ bond length in benzene is $...... \ \mathring{A}$

Predict the major product of the reaction of $1$-ethyl-$3$-methylbenzene with $KMnO_4$ in an acidic medium under heating.

Which of the following would be most reactive towards nitration?

Among the following,the aromatic compound is:

What are $X$ and $Y$ in the following reaction sequence?
$CH_3(CH_2)_5CH_3 \stackrel{X}{\longrightarrow} C_7H_8 \stackrel{Br_2}{\Delta} Y$

Identify the aromatic compound.