The correct order of reactivity towards Electrophilic Substitution Reaction $(E.S.R.)$ for the following compounds is:
$(i)$ Toluene
(ii) $m$-Methoxytoluene
(iii) Benzaldehyde
(iv) $p$-Nitrobenzaldehyde

The reaction$(s)$ leading to the formation of $1,3,5-$trimethylbenzene is (are):
$(A)$ $3CH_3COCH_3 \xrightarrow{Conc. H_2SO_4, \Delta} 1,3,5-\text{trimethylbenzene}$
$(B)$ $3CH_3C \equiv CH \xrightarrow{\text{heated iron tube}, 873 K} 1,3,5-\text{trimethylbenzene}$
$(C)$ $1,3,5-\text{triacetylbenzene} \xrightarrow{1) Br_2, NaOH, 2) H_3O^+, 3) \text{sodalime}, \Delta} \text{benzene}$
$(D)$ $1,3,5-\text{triformylbenzene} \xrightarrow{Zn/Hg, HCl} 1,3,5-\text{trimethylbenzene}$

Which of the following compounds are aromatic?

Identify the product $(P)$ formed from the following reaction.

Explain the mechanism of the first and second steps of the general electrophilic substitution reaction for benzene.

Which compound is formed when benzene is boiled with concentrated $HCl$?