Which of the following groups is an ortho and para directing group?

Which of the following compounds has difficulty in breaking the $C-X$ bond during a nucleophilic substitution reaction?

Among the following,the hydrolysis reaction that takes place at the slowest rate is:

Which of the following possesses the highest melting point?

Nitrobenzene on reaction with conc. $HNO_3/H_2SO_4$ at $80-100 \ ^oC$ forms which one of the following products?

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