The Hinsberg reagent is:

Considering the basic strength of amines in aqueous solution,which one has the smallest $pK_b$ value?

Identify $X$ and $Y$ in the following reactions:

Give uses of amine compounds as medicines.

The major product $B$ in the following reaction sequence is:
$CH_3-CH_2-CH(CH_3)-CONH_2$ $\xrightarrow{Br_2/KOH, \Delta} (A)$ $\xrightarrow{(1) CH_3I (excess), (2) AgOH/\Delta} (B)$

$(A)$ $\xrightarrow[(1) \text{ excess } CH_3I/K_2CO_3, (2) \text{ } Ag_2O/H_2O, (3) \text{ } \Delta]{} (B)$ $\xrightarrow[(i) \text{ excess } CH_3I/K_2CO_3, (ii) \text{ } Ag_2O, (iii) \text{ } \Delta]{} H_2C=CH-CH(CH_3)-CH=CH_2$. Identify $(A)$.