The
electrode reactions are complex, but they can be written
approximately as follows :
Anode:
Zn(s) ¾® Zn2+ + 2e–
Cathode:
MnO2+ NH4
++ e–¾® MnO(OH) + NH3
In the reaction at cathode, manganese is reduced
from the + 4 oxidation state to the +3 state Ammonia
produced in the reaction forms a complex with Zn2+ to give
[Zn (NH3)4]2+ The cell has a potential of nearly 1 5 V