In acidic solution, which is the correct balanced reduction half-reaction for MnO4− to Mn2+?

• A. MnO4− + 4 H+ + 3 e− → Mn2+ + 2 H2O
• B. MnO4− + 8 H+ + 5 e− → Mn2+ + 4 H2O
• C. MnO4− + 2 H+ + e− → MnO2 + H2O
• D. MnO4− + 8 OH− + 5 e− → MnO2 + 4 H2O

Answer: (B)