Answer to Question #151120 in General Chemistry for Cell

Question #151120

Mercury cell is used for pacemakers, hearing aids, electric watches, and light meters. The reactions involved are:
Oxidation: Zn → ZnO Reduction: HgO → Hg

Complete and balance the half reactions in basic basic medium since the electrolye used in mercury cell is KOH. Give the overall balanced equation.

Expert's answer

balanced Oxidation:

Zn + 2OH– → ZnO + H2O + 2e–

balanced Reduction:

HgO + H2O + 2e → 2OH– + Hg

overall balanced equation:

Zn + HgO → Hg + ZnO