How will you prepare aldehydes from nitriles ? (Stephan’s reaction)

Explanation

Stephen.s reaction : It involves partial reduction of alkyl or aryl cyanide with a suspension of anhydrous `SnCl_(2)` in ether saturated with HCl at room temperature followed by hydrolysis to give an aldehyde. For example
`SnCl_(2) + 2HCl rarr SnCl_(4) + 2[H]`
`underset("Methyl cyanide")(CH_(3)-C) -= N + 2[H] + HCl rarr CH_(2) - CH = NH.HCl underset("Base")overset(H_(2)O)rarr underset("Acetaldehyde")(CH_(3)CHO) + NaCl`
`underset("Phenyl cyanide")(C_(6)H_(5)-C-=N) + 2[H] + HCl rarr C_(6)H_(5) - CH = NH.HCl underset("Base")overset(H_(2)O)rarr underset("Benzaldehyde")(C_(6)H_(5)CHO) + NH_(4)Cl`