Amongst the compounds given,the one that would form a brilliant colored dye on treatment with $NaNO_2$ in dil. $HCl$ followed by addition to an alkaline solution of $\beta$-naphthol is

How many of the transformations given below would result in aromatic amines?

$A$ student has planned to prepare acetanilide from aniline using acetic anhydride. The student has started from $9.3 \ g$ of aniline. However, the student has managed to obtain $11 \ g$ of dry acetanilide. The $\%$ yield of this reaction is $.....$ (in $\%$)

The final product $A$, formed in the following multistep reaction sequence is:

In the hydrolysis of aniline,the reagent used is:

$A$ hydrocarbon $'A'$ $(C_4H_8)$ on reaction with $HCl$ gives a compound $'B'$ $(C_4H_9Cl)$,which on reaction with $1 \ mol$ of $NH_3$ gives compound $'C'$ $(C_4H_{11}N)$. On reacting with $NaNO_2$ and $HCl$ followed by treatment with water,compound $'C'$ yields an optically active alcohol,$'D'$. Ozonolysis of $'A'$ gives $2 \ mols$ of acetaldehyde. Identify compounds $'A'$ to $'D'$. Explain the reactions involved.