In the reaction of oxalate with permanganate in acidic medium, the number of electrons involved in producing one molecule of CO₂ is :

Which of the following reactions is an example of a redox reaction?

The volume of 0.1N dibasic acid sufficient to neutralize 1 g of a base that furnishes 0.04 mole of OH⁻ in aqueous solution is :

In which of the following reactions H₂O₂ acts as a reducing agent?
1. H₂O₂ + 2H⁺ + 2e^- $$\to$$ 2H₂O
2. H₂O₂ - 2e^- $$\to$$ O₂ + 2H⁺
3. H₂O₂ + 2e^- $$\to$$ 2OH^-
4. H₂O₂ + 2OH^- - 2e^- $$\to$$ O₂ + 2H₂O