$A$ mixture of benzene and aniline can be separated by

The above $(C-N)$ coupling reaction takes place at

The reduction of benzenediazonium chloride to phenylhydrazine can be accomplished by:

Which one of the following compounds gives carboxylic acid with $HNO_2$?

In the reaction sequence $CH_3Cl$ $\xrightarrow{KCN}$ $\xrightarrow{+4H} A$ $\xrightarrow{NaNO_2/HCl} \text{Ethyl alcohol} + ?$. What are the major and minor products formed?

An organic compound $[A]$ $(C_4H_{11}N)$ shows optical activity and gives $N_2$ gas on treatment with $HNO_2$. The compound $[A]$ reacts with $PhSO_2Cl$ producing a compound which is soluble in $KOH$. The structure of $A$ is: