Find $B$ in the following reaction sequence:

The following is a confirmatory test for aromatic primary amines. Identify reagent $(A)$ and $(B)$.

In the carbylamine reaction,hot alcoholic $KOH$ and ...... are required.

In the reaction,$P, Q$ and $R$ respectively are:

Hoffmann bromamide degradation of benzamide gives product $A$,which upon heating with $CHCl_{3}$ and $NaOH$ gives product $B$. The structures of $A$ and $B$ are

When a concentrated solution of sulphanilic acid and $1-$naphthylamine is treated with nitrous acid $(273 \ K)$ and acidified with acetic acid,the mass $(g)$ of $0.1 \ mole$ of product formed is : (Given molar mass in $g \ mol^{-1} H: 1, C: 12, N: 14, O: 16, S: 32$)