sir plz give me the explanation about stephen's reaction

Stephen's reaction or Stephen Aldehyde Synthesis:

The Stephen's reaction is used to prepare aldehydes from nitriles or cyanides. The reduction of nitriles with stannous chloride and hydrogen chloride in ethyl acetate solvent produces imine intermediate. The hydrolysis of this intermediate with water gives the corresponding aldehyde.

           SnCl₂                                            H₂O

R-CN -----------------> [R-CH=NH2+ ][Cl-] ---------> R-CHO

            HCl

Example :

Methyl cyanide to acetaldehyde preparation by stephen’s reaction is as follows:

CH₃CN + 2[H] ---(SnCl₂/HCl)----------> CH₃-CH-NH ---(H₂O)----> CH₃CHO + NH₃