Nitrobenzene on nitration gives

In a reaction of $C_6H_5Y$,the major product obtained is the $60\%$ isomer. What is the group $Y$?

Which of the following will undergo Friedel-Crafts alkylation with $CH_3Cl$ / anhy. $AlCl_3$?

$A$ major component of Borsch reagent is obtained by reacting hydrazine hydrate with which of the following?

Which of the following compounds has a dipole moment approximately equal to that of chlorobenzene?

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