Determination of Ksp Values Using the Nernst Equation If Keq can be determined then it is reasonable to assume that other equilibrium constants can be determined by using half-cell reaction.  By measuring the voltage of an appropriate cell we can calculate the Eo value. The electrochmeical call for determining the Ksp for AgCl is below. In this cell, the anode consists of a piece of metallic silver immersed in a 1 M Cl-1 ion solution with excess AgCl(s).  The cathode is a standard Ag(s) |  Ag+1 half cell. The schematic is:                         Ag |  AgCl(s) | Cl-1 (1 M) || Ag+1 (1 M) |  Ag(s) The anode half cell potential at SATP is -0.22 V for the reaction:    Ag(s)  + Cl-1  --->  AgCl(s) +  e-1 The standard state cathode potential for silver is +0.80 V.    Ag+1  + e-1 ---> Ag(s)   Eo = +0.80 V Therefore -0.22 V + 0.80 V= 0.58 V is the overall reaction potential for  Ag+1  + Cl-1 ---> AgCl(s) At equilibrium Ecell = 0 Therefore     0 = 0.58 V - 0.059/1 log (1 / [Ag+1][Cl-1])                     -0.58 V = 0.059 log [Ag+1][Cl-1]                     -0.58 V = 0.059 log Ksp                     log Ksp = -9.8                     Ksp = 10-9.8                            = 1.6 X 10-10