Zinc/silver oxide cell is used in hearing aids and electric watches. The following reactions occur :
`Zn(s) to Zn^(2+)(aq)+2e^(-) , E_(Zn^(2+)//Zn)^(@)=-0.76V`
`Ag_(2)O+H_(2)O+2e^(-) to2Ag+2OH^(-),E_(Ag^(+)//Ag)^(@)=0.344" V"`
Calculate (i) Standard potential of the cell (ii) Standard Gibbs energy.

Explanation

In this reaction, Zn is oxidised and `Ag_(2)O` is reduced
(i)`" "E_(cell)^(@)=E_(cathode)^(@)-E_(anode)^(@)`
`=(0.344)-(-0.76)=1.104" V"`
(ii) `" " DeltaG^(@)=-nFE_(cell)^(@)`
`=-2xx(96500" C mol"^(-1))xx(1.104" V")`
`=-2.13xx10^(5)" CV "mol^(-1)`
`=-2.13xx10^(5)" J mol"^(-1)`