Aniline is purified by which of the following methods?

Total number of secondary amines (excluding stereoisomers) possible with the molecular formula $C_5H_{13}N$ is

Which of the following is the strongest Bronsted base?

When $R-CO-NH_2$ is treated with $Br_2$ and $KOH$,it gives $R-NH_2$ as the major product. Which intermediate is involved in this reaction?

The major products obtained from the following sequence of reactions are
$(CH_3)_2CHCH_2N(CH_2CH_3)_2$ $\xrightarrow{CH_3I}$ $\xrightarrow[H_2O]{Ag_2O}$ $\xrightarrow{\Delta} \text{products}$

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