Question

Sometimes the cell reaction of nickel-cadmium batteries is written with cd metal as the anode and solid nio2 as the cathode. assuming that the products of the electrode reactions are solid hydroxides of cd(ii) and ni(ii), respectively, write balanced chemical equations for the cathode and anode half-reactions and the overall cell reaction. include the phases of all species in the chemical equation.

Answer 1

The cell reaction of nickel-cadmium batteries are as follows:

At Anode   :     Cd(s)   +    2OH-(aq.)    →    Cd(OH)2(s)    +     2e-
At cathode:   NiO2(s)   +   2H2O(l)   +   2e-   →   Ni(OH)2
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Overall reaction:  Cd(s) + NiO2(s)   +   2H2O  →   Cd(OH)2(s)   +   Ni(OH)2 (s)