Which of the following is used as a catalyst in the manufacture of toluene from benzene with $CH_3Cl$?

The increasing order of the following compounds for electrophilic substitution reaction is:
$(I)$ Toluene
$(II)$ Benzene
$(III)$ Benzoic acid

Hexane $\xrightarrow[\substack{773 \ K \\ 10-20 \ atm}]{Cr_2O_3} X$ $\xrightarrow[\text{Anhydrous } AlCl_3]{CH_3COCl} Y$. $Y$ in the above sequence of reactions is

Consider the following reactions:
$Ethylbenzene \xrightarrow[(ii) H_3O^{+}]{(i) KMnO_4-KOH/\Delta} Y$
$Propylbenzene \xrightarrow[(ii) H_3O^{+}]{(i) KMnO_4-KOH/\Delta} Z$
What are the structures of $Y$ and $Z$?

Which active species is involved in the nitration of benzene with concentrated nitric acid and concentrated sulfuric acid?

Identify the compound $(X)$ in the following reaction:
[Image of $1,3$-dinitrobenzene reacting with $HNO_3 + H_2SO_4$ to form $(X)$]
Compound $(X)$ is: