Question

Alkaline cell uses zinc and MnO2 like dry cell. KOH is the electrolyte. The cell reaction is Zn+MnO2 → ZnO+Mn203

Complete and balance this reaction in basic medium.

Answer 1

Solution:

1) Oxidation half reaction:

$Zn+H_2O+2OH^-\implies\;ZnO+2H^++2OH^-+2e^-$

2) Reduction half reaction:

$2MnO_2+2H^++2OH^-+2e^-\implies\;Mn_2O_3+H_2O+2OH^-$

3) Overall redox reaction:

$Zn+2MnO_2\implies\;ZnO+Mn_2O_3$