(b)
$RCN\ \overset{Hydrolysis\ }{\rightarrow}RCOOH + NH_{3}$
$RCH = NOH\overset{Reduction\ \ }{\rightarrow}RCH_{2}NH_{2} + H_{2}O$
$RCN + 2H_{2}O\overset{\ \ \mathrm{\Delta}\ \ \ }{\rightarrow}RNH_{2} + HCOOH$
$RCONH_{2}\overset{Hydrolysis\ }{\rightarrow}RCOOH + NH_{3}$