AgCl(s)+e↔Ag(s) +Cl- Eo=0.197V (anode)
Ag+ +e↔Ag(s) Eo=0.799V (cathode)
Ecell={Eo-0.0591 log1/[Ag+]}-{Eo-0.0591 log1/[Cl-]}
But for reference cell with constant potential,
Ecell ={Eo-0.0591
log1/[Ag+]}Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
[since 0.0591 log1/[Cl-]}=constant as [Cl-]=constant]
Eocell=0.799V-0.197V=0.602
Ecell=0.602V-0.0591 log1/[Ag+]
Total Cl- in 100 ml=0.100M*100/1000L=0.01 moles
Now, after 75 ml titrant is added, 75% of Cl- is titrated,so
only 25% of cl- remain in solution
[Cl-]=fraction in solution*original concentration*initial
volume/total volume=0.25*0.1M*100/175=0.0143M
Ag++Cl-→AgCl
Ksp=1.8*10^-10=[Ag+][Cl-]
Or, 1.8*10^-10=[Ag+][Cl-]=[Ag+]*(0.0143M)
[Ag+]=1.8*10^-10/0.0143M=125.87 *10^-10=1.25*10^-8M
Ecell=0.602V-0.0591 log1/[Ag+]
       =0.602V-0.0591 log
1/(1.25*10^-8)
       =0.602V+0.0591
V*log(1.25*10^-8)
     Â
      =0.602V-0.0591V *(-7.91)
=0.602-0.467
Ecell=0.135V
