Nessler's reagent is

An aromatic compound $A$ reacts with $Zn/NH_4Cl$,and the filtrate is then added to an ammoniacal silver nitrate solution,resulting in a black precipitate. Which group does compound $A$ contain?

$A$ positive carbylamine test is given by

An organic compound $A$ on treatment with benzene sulphonyl chloride gives compound $B$. $B$ is soluble in dil. $NaOH$ solution. Compound $A$ is:

The Hinsberg's method is used for

Which of the following will release $NH_{3}$ upon reaction with $NaOH$?