Isomeric amines with molecular formula C 8 H 11 N give the following tests Isomer P ⇒ Can be prepared…

The isomers of ${\mathrm{C}}_8{\mathrm{H}}_{11}\mathrm{N}$, that can be prepared by Gabriel phthalimide synthesis are primary amines.

 

can be prepared by Gabriel phthalimide synthesis because ${\mathrm{S}}_{\mathrm{N}}2$ is possible in

Secondary amines react with Hinsberg’s reagent to give solid insoluble in $\mathrm{NaOH}$. Hence, Q is the secondary amine

Aromatic amines like aniline give diazonium salts. The diazonium salt used in diazo coupling to get red dye with beta Naphthol in sodium hydroxide. Hence, R is aromatic amine as shown below.