Question

Compound decomposes through the following unbalanced reaction in acidic media: MnO2→ MnO4-(s) + Mn2+(s) Balance this reaction and use the information to answer the following three (3) questions. 14. What is the reducing agent?

A) H+
B) H2O
C) MnO2
D) MnO4-
E) Mn2+

Answer 1

C) MnO₂

Step-by-step explanation:

If we write the semi equations (this is, for reduction and oxidation) we will have:

Oxidation: 2MnO₂ → MnO₄⁻ + Mn⁺²

Reduction: 2H₂O → H₂ + 2OH⁻

Then the final global reaction (just adding the two above hemi chemical reactions):

2MnO₂ + 2H₂O → MnO⁻₄ + Mn⁺² + H₂ + 2OH⁻ (in acidic media)

So, we have Mn⁺⁴ (from MnO₂) goes to Mn⁺⁷ and Mn⁺² (this is, Mn is oxidated) and H⁺ (from acidic media or H₂O) goes to H₂ (this is, it is reduced). So the reducing agent would be MnO₂