Answer to Question #267747 in General Chemistry for two

Question

In acidic solution, O3 and Mn2+ ions react spontaneously:

O3(g) + Mn2+(aq) + H2O(l) ⟶

O2(g) + MnO2(s) + 2H+(aq) E°

cell = 0.84 V

(a) Write the balanced half-reactions.

(b) Using Appendix D to find E°

ozone, calculate E°

manganese.

Answer 1

Step 1. Separate the whole reaction into half-reactions

*ignore H₂O(l) and H⁺

O₃(g) ⟶ O₂(g)

Mn²⁺(aq) ⟶ MnO₂(s)

Step 2. Balance the non-hydrogen and non-oxygen elements first

O₃(g) ⟶ O₂(g)

Mn²⁺(aq) ⟶ MnO₂(s)

Step 3. Balance oxygen by adding H₂O to the side that needs oxygen (1 O: 1 H₂O)

O₃(g) ⟶ O₂(g) + H₂O(l)

Mn²⁺(aq) + 2 H₂O(l) ⟶ MnO₂(s)