Question

How can you show that H₂O₂ works both as oxidizing and reducing agent by giving examples.

Answer 1

Oxidising properties. H₂O₂ has a tendency to accept electrons in chemical reactions and thus behaves as an oxidizing agent in both acidic and alkaline medium. 

(a) In acidic medium 

H₂O₂ → H₂O + O 

H₂O₂ + 2H⁺ + 2e^– → 2H₂O

Example: 

2Fe²⁺ + 2H⁺ + H₂O₂ → 2Fe³⁺ + 2H₂O 

b) In alkaline medium H₂O₂ + OH^– + 2e^– 

Example: 

Reducing properties. H₂O₂ can give electrons in a few reactions and thus behaves as a reducing agent. 

a) In acidic medium, 

H₂O₂ → O₂ + 2H⁺ + 2e^–

b) In alkaline medium, 

H₂O₂ + 2OH^– → 2H₂O + O₂ + 2e^–

2Fe³⁺ + H₂O₂ + 2OH^– → 2Fe²⁺ + O₂ + 2H₂O