Explain the method of preparation of amine compounds by the reduction of nitrile and amide compounds.

Reduction of nitriles: Nitriles on reduction with lithium aluminium hydride $(LiAlH_{4})$ or catalytic hydrogenation produce primary amines. This reaction is used for the ascent of the amine series,i.e.,for the preparation of amines containing one carbon atom more than the starting nitrile.
Reduction of amides: The amides on reduction with lithium aluminium hydride yield primary amines.
$R-C \equiv N \xrightarrow{H_{2}/Ni \text{ or } Na(Hg)/C_{2}H_{5}OH} R-CH_{2}-NH_{2}$
$CH_{3}-C \equiv N \xrightarrow{H_{2}/Ni \text{ or } Na(Hg)/C_{2}H_{5}OH} CH_{3}-CH_{2}-NH_{2}$
$R-CONH_{2} \xrightarrow{LiAlH_{4} / H_{2}O} R-CH_{2}-NH_{2}$
$CH_{3}-CONH_{2} \xrightarrow{LiAlH_{4} / H_{2}O} CH_{3}-CH_{2}-NH_{2}$