Question

Ferric chloride is reduced when zinc and hydrochloric acid are added to its solution and not by passing H₂ gas through its solution. Explain.

Answer 1

Ordinary H₂ is less reactive and therefore, it does not reduce acidified FeCl₃ solution. However, when zinc is added to acidified FeCl₃ solution, nascent hydrogen is produced which has enormous energy. It is more reactive than ordinary H₂ and reduces acidified FeCl₃ solution. 

FeCl₃ + H₂ → No reaction; 

Zn + H₂SO₄ → ZnSO₄ + H₂