Isomer $(P) \Rightarrow$ Can be prepared by Gabriel phthalimide synthesis
Isomer $(Q) \Rightarrow$ Reacts with Hinsberg's reagent to give solid insoluble in $NaOH$
Isomer (R) $\Rightarrow$ Reacts with $HONO$ followed by $\beta$-naphthol in $NaOH$ to give red dye.
Isomers $( P ),( Q )$ and $( R )$ respectively are

${C_6}{H_5} - N{O_2} + 6[H] \to {C_6}{H_5} - N{H_2} + 2{H_2}O$
The reducing agent used in this reaction is …….



