$A$ mixture of ethyl amine,chloroform,and alcoholic $KOH$ on heating gives:

$R$ is

The correct statements of the following are:
$A$. Aniline forms a stable benzene diazonium chloride at $285 \ K$.
$B$. $N$-Phenylethanamide is less reactive towards nitration than aniline.
$C$. $p-CH_3C_6H_4COCl$ is Hinsberg reagent.

Which of the following compounds reacts with $CHCl_3$ and $KOH$ to produce an isocyanide?

What is the final product $C$ in the reaction sequence: $CH_3CH_2NH_2$ $\xrightarrow{HNO_2} A$ $\xrightarrow{PCl_5} B$ $\xrightarrow{NH_3} C$?

Which of the following has the maximum nucleophilicity?