${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}\equiv \mathrm{N}+\left[\mathrm{H}\right]\stackrel{{\mathrm{SnCl}}_2/\mathrm{HCl}}{⟶}{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{CHO}+{\mathrm{NH}}_3$.

The above reaction is

Phenyl cyanide is reduced into benzaldehyde in the presence of SnCl₂ /HCl reagent. This reaction is known as Stephen’s reaction.

$\begin{array}{l}{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}\equiv \mathrm{N}+2\left[\mathrm{H}\right]\frac{{\mathrm{SnCl}}_2}{\mathrm{HCl}}\\ {\mathrm{C}}_6{\mathrm{H}}_5\mathrm{CH}=\mathrm{NH}\stackrel{{\mathrm{H}}_2\mathrm{O}/{\mathrm{H}}^{+}}{⟶}{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{CHO}+{\mathrm{NH}}_3\end{array}$