Question

when benzyl chloride is boiled with aqueous `KOH` solution and the solution is acidified by a few drops of dilute `HNO_(3)` followed by `AgNO_(3)` solution, a white precipitate is formed. However, no such precipitate is noticed when the reaction is carried with chlorobenzene. explain.

Answer 1

In case of `C_(6)H_(5)CH_(2)Cl`, the benzyl carbocation `(C_(6)H_(5) overset(o+)(C)H_(2))` formed by releasing `Cl^(-)` ion is resonance stabilised. Therefore, the `C - Cl` bond can cleave to form `KCl`. However, the phenyl carbocation `(C_(6)overset(o+)(H)_(5))` expected to be formed in case of chlorobenzene does not show any resonance. therefore, `C - Cl` bond does not cleave in case of chlorobenzene and no white precipitate is formed in this case.