An example of a disproportionation reaction is :

The correct statement among the following is :

Given

CO³⁺ + e^– $$ \to $$ CO₂⁺ ; E^o = + 1.81 V

Pb⁴⁺ + 2e^– $$ \to $$ Pb₂⁺ ; E^o = + 1.67 V

Ce⁴⁺ + e^– $$ \to $$ Ce³⁺ ; E^o = + 1.61 V

Bi³⁺ + 3e^– $$ \to $$ Bi ; E^o = + 0.20 V

Oxidizing power of the species will increase in the order :

The metal that gives hydrogen gas upon treatment with both acid as well as base is :