$R$ is

$Br-CH_2-(CH_2)_2-CH_2-Br + CH_3NH_2 \to$ The product of the reaction is:

Identify $(a)$ and $(b)$ in the following reaction:
$CH_3CH_2NH_2 + CHCl_3 + 3KOH \rightarrow (a) + (b) + 3H_2O$

When primary amines are treated with $HCl$,the product obtained is

Assertion : Boiling and melting points of amides are higher than corresponding acids.
Reason : It is due to strong intermolecular hydrogen bonding in their molecules.

Arrange the following compounds in their correct order of $pK_b$ values.