Heating chlorobenzene with aqueous $NH_3$ in the presence of $Cu_2Cl_2$ gives ..........

The following reaction is:
$p-Nitrochlorobenzene + KOH \xrightarrow{\Delta} p-Nitrophenol + KCl$

Diphenyls are a potential threat to the environment. How are these produced from aryl halides?

In the following reaction,the compound $C$ is:
${C_7}{H_8}$ $\xrightarrow[\Delta]{3Cl_2} A$ $\xrightarrow{Br_2/Fe} B$ $\xrightarrow{Zn/HCl} C$

Nitrobenzene on further excessive nitration gives

Arrange the following compounds in order of increasing dipole moment.
$(I)$ Toluene
$(II)$ $m$-dichlorobenzene
$(III)$ $o$-dichlorobenzene
$(IV)$ $p$-dichlorobenzene