Question

Write electrode reactions and overall cell reaction when Leclanche's dry cell generates electricity.

Answer 1

Electrode reactions are as follows:

1. Oxidation at anode:
   \[\ce{Zn_{(s)} -> Zn^{2+}_{ (aq)} + 2e^{-}}\]
2. Reduction at cathode:
   \[\ce{2NH^{+}_{4(aq)} + 2MnO_{2(s)} + 2e^{-} -> Mn_2O_{3(s)} + 2NH_{3(aq)} + H_2O_{(l)}}\]
3. Overall cell reaction:
   \[\ce{Zn_{(s)} + 2NH^+_{4(aq)} + 2MnO2 -> Zn^{2+}_{ (aq)} + Mn2O_{3(s)} + 2NH_{3(aq)} + H2O_{(l)}}\]