Identify and give the definition of the oxidizing agent for this chemical reaction.

Question

Identify and give the definition of the oxidizing agent for this chemical reaction. Show how are you correct by determining the oxidation states for all the elements and labeling the oxidized and reduced species on both sides of the chemical reaction:

2MnO₄^- + 5H₂SO₃ --> 2Mn²⁺ + 5SO₄^2- + 4H⁺ + 3H₂O

Answer 1

An oxidizing agent is an agent that itself becomes reduced, i.e. it gains electrons.

A reducing agent is an agent that itself becomes oxidized, i.e. it loses electrons.

2MnO₄^- + 5H₂SO₃ --> 2Mn²⁺ + 5SO₄^2- + 4H⁺ + 3H₂O

S on the left side of the equation has an oxidation number of 4+. On the right side it has an oxidation number of 6+. Thus, S has lost 2 electrons, has become more positive and thus has been oxidized. This makes it a reducing agent. So, the reducing agent in this reaction is H2SO3.

Mn on the left side of the equation has an oxidation number of 7+. On the right side it has an oxidation number of 2+. Thus, Mn has gained 5 electrons, has become more negative (less positive) and thus has been reduced. This makes it an oxidizing agent. So, the oxidizing agent is MnO4^-