A disproportionation reaction is an oxidationreduction reaction in which the same substance is oxidized and reduced. Complete

Question:

A disproportionation reaction is an oxidation–reduction reaction in which the same substance is oxidized and reduced. Complete and balance the following disproportionation reactions:
(a) Ni⁺(aq) → Ni²⁺(aq) + Ni(s) (acidic solution)
(b) MnO₄^2-(aq) → MnO₄^-(aq) + MnO₂(s) (acidic solution)
(c) H₂SO₃(aq) → S(s) + HSO₄^-(aq) (acidic solution)
(d) Cl₂(aq) → Cl^-(aq) + ClO^-(aq) (basic solution)