Practice Problem 4

Which of the following is the strongest oxidizing agent?

(a) H₂O₂ in acid

(b) H₂O₂ in base

(c) MnO₄^- in acid

(d) MnO₄^- in base

(e) CrO₄^2- in acid

Answer

We start by searching the table of standard-state reduction potentials for the reduction half-cell potential for the oxidizing agent in each of these solutions.

(a) H2O2 + 2 H+ + 2 e- 2 H2O		Eored = 1.776 V
(b) H2O2 + 2 e- 2 OH-		Eored = 0.88 V
(c) MnO4- + 8 H+ + 5 e- Mn2+ + 4 H2O		Eored = 1.491 V
(d) MnO4- + 2 H2O + 3 e- MnO2 + 4 OH-		Eored = 0.588 V
(e) CrO42- + 8 H+ + 3 e- Cr3+ + 4 H2O		Eored = 1.195

According to these data, the strongest oxidizing agent is H₂O₂ in acid.