State and explain Nernst equation with the help of a metallic electrode and a non-metallic electrode.

Explanation

The electrode potential at any concentration measured with respect to standard hydrogen electrode is represented by Nernst equation.
Nernest equation is
`E=E^(0) +(RT)/(nF) ln [M^(+)]` [Metal Electrodes]
Given electrode reaction is
`M_((aq))^(n+)+n e^(-)hArrM_((s))`
For the above electrode reaction Nerst equation is
`E_((M^(n+)//M))=E_((M^(n+)//M))+(RT)/(nF) ln [M^(n+)]`
Here `E_((M^(n+)//M))=` Electrode potential
`E_((M^(n+)//M))^(0) =` Standard Electrode potential
R = gas constant `=8.314J //K.` mole
F = Faraday `=96487c//` mole
T = temperature
`[M^(n+)]` concentration of species `M^(n+)`
For non-metal electrodes :
`E=E^(0)-(RT)/(nF)ln C,C=` concentration
Example for metal electrode :
Given cell is `Ni_((s))|Ni_((aq))^(2+)||Ag _((aq))^(+)|Ag`
Nernest equation for the cell is
`E_(cell) =E_(cell)^(0) +(RT)/(nF)ln ""([Ag^(+)])/([Ni]^(+2))`
Example for non-metal electrode : `pt, Cl_(2) //Cl^(-)`
`E=E^(0) -(RT)/(nF)log C`
`E=E^(0)-(RT)/(F)log C`