The correct option is C E0Cl−/AgCl/Ag=RTF ln Ksp+E0Ag+/Ag
The given electrode is a metal/metal insoluble salt electrode.
Here the silver rod is coated with a paste of saturated AgCl and dipped in a solution of ionic electrolyte of KCl.
The electrode reaction is,
AgCl(s)+e−→Ag(s)+Cl−
Derivation:
AgCl(s)⇌Ag+(aq)+Cl−(aq)......(1)
ΔG1=ΔG0+RTln Q
At equilibrium,
ΔG1=0
Q=Ksp
ΔG01=−RT ln Ksp
Ag+(aq)+e−→Ag(s)........(2)
ΔG02=−nFE0Ag+/Ag
Adding equation (1) and (2)
AgCl(s)+e−→Ag(s)+Cl−.......(3)
ΔG03=−nFE0Cl−/AgCl/Ag
Adding equation (1) and (2) gives (3)
∴
ΔG03=ΔG01+ΔG02
−nFE0Cl−/AgCl/Ag=−RT ln Ksp−nFE0Ag+/Ag
nFE0Cl−/AgCl/Ag=RT ln Ksp+nFE0Ag+/Ag
E0Cl−/AgCl/Ag=RTnF ln Ksp+nFE0Ag+/Ag
n=1 for given electrode reaction,
E0Cl−/AgCl/Ag=RTF ln Ksp+E0Ag+/Ag