How will you convert benzene into:
$(i)$ $p-nitrobromobenzene$
$(ii)$ $m-nitrochlorobenzene$
$(iii)$ $p-nitrotoluene$
$(iv)$ acetophenone

(N/A) $(i)$ Benzene is first brominated with $Br_2$ in the presence of anhydrous $FeBr_3$ to form bromobenzene. Bromobenzene is then nitrated with a mixture of conc. $HNO_3$ and conc. $H_2SO_4$ at $323-333 \ K$ to give a mixture of $o-$ and $p-nitrobromobenzene$. The $p-isomer$ is separated by fractional distillation.
$(ii)$ Benzene is first nitrated with a mixture of conc. $HNO_3$ and conc. $H_2SO_4$ at $323-333 \ K$ to form nitrobenzene. Nitrobenzene is then chlorinated with $Cl_2$ in the presence of anhydrous $AlCl_3$ to give $m-nitrochlorobenzene$ (since the $-NO_2$ group is meta-directing).
$(iii)$ Benzene is first alkylated with $CH_3Cl$ in the presence of anhydrous $AlCl_3$ to form toluene. Toluene is then nitrated with a mixture of conc. $HNO_3$ and conc. $H_2SO_4$ at $323-333 \ K$ to give a mixture of $o-$ and $p-nitrotoluene$. The $p-isomer$ is separated by fractional distillation.
$(iv)$ Benzene undergoes Friedel-Crafts acylation with acetyl chloride $(CH_3COCl)$ in the presence of anhydrous $AlCl_3$ to form acetophenone.