Hydrolysis of alkyl isocyanide yields:

Which of the following amines has the lowest $pK_{b}$ value?

$9.3 \ g$ of pure aniline is treated with bromine water at room temperature to give a white precipitate of the product '$P$'. The mass of product '$P$' obtained is $26.4 \ g$. The percentage yield is $......... \ \%$.

Identify the products $y$ and $x$ in the following reaction sequence:
$C_6H_5CONH_2 \xrightarrow{NaOBr} y$
$C_6H_5CONH_2 \xrightarrow[(ii) H_3O^+]{(i) C_6H_5SO_2Cl / py, \Delta} x$

Which among the following compounds is a secondary amine?

Consider the molecule $1,3-dimethyl-1,2,3,4-tetrahydroquinoxaline$ with an amino group at the $5$-position. Upon protonation,which nitrogen atom is the most basic and will be protonated first? Identify the correct structure of the product '$A$' formed after protonation.