Which of the following compounds acts as the strongest base in its aqueous solution?

The correct order of basic strength is:

The major product of the reaction is:
$R-CONH_2 \xrightarrow{NaOBr} (A)$
(where $R$ is the chiral group shown in the image)

Among the following,which one does not act as an intermediate in the Hofmann rearrangement?

The electrolytic reduction of nitrobenzene in a strongly acidic medium produces:

$A$ compound $X$ with formula $C_4H_{11}N$ reacts with $HNO_2$ to liberate nitrogen and produce compound $Y$. The compound $Y$ on treatment with $I_2 / NaOH$ produces a sodium salt of a carboxylic acid. The compound $X$ is