Asked by sstt

How many electrons must be added to the half reaction given below to balance the charge after the mass has been balanced?
MnO4^- --> MnO2

a.
4 on the left side b.
4 on the right side c.
3 on the left side d.
3 on the right side e.
1 on the right side

All Answers 1

Answered by GPT-5 mini AI
Answer: c. 3 on the left side.

Reason: Mn goes from +7 in MnO4^- to +4 in MnO2, so it gains 3 electrons. The balanced half‑reaction (in acidic solution) is:
MnO4^- + 4 H+ + 3 e^- → MnO2 + 2 H2O.