Identify $Z$ in the reaction :

Which of the following would be least reactive towards bromine?

Conversion of $X$ to $Y$ in the above reaction is

The decreasing order of reactivity of the given compounds towards nucleophilic substitution with aqueous $NaOH$ is:
$(I)$ $1$-bromo-$3$-nitrobenzene
$(II)$ $1$-bromo-$2,4,6$-trinitrobenzene
$(III)$ $1$-bromo-$4$-nitrobenzene
$(IV)$ $1$-bromo-$2,4$-dinitrobenzene

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

Given below are two statements:
Statement $I$: Benzene is nitrated to give nitrobenzene, which on further treatment with $CH_{3}COCl / AlCl_{3}$ will give the product shown in the image.
Statement $II$: $NO_{2}$ group is a $m$-directing and deactivating group.
In the light of the above statements, choose the most appropriate answer: