How Does Electrochemistry Calculate the Solubility of AgI?

[koomanchoo]

hey i seem to be having a lot of trouble qith this question may i get some help?
The standard potential of the cell below is + 0.9509 V at 25 oC. Calculate the solubility, normally called s, of AgI (Note: Enter the natural log of s (ln s) as your answer)

Ag|AgI(s)|AgI(aq)|Ag

i'm using nernst equation and found the standard potential for Ag+,Ag to be 0.7991V

i am using Eo as 0.7991 and E as 0.9509 and rearanging the equation to find the solubility as LnS.. the correct answer is suppose to be -18.51.. where i am going wrong? please help.
thanks

n.b standard reduction potential of AgI(s) is -.15V

 

[Borek]

IIRC -18.51 is not a natural log of the AgI solubility product - it's decimal log.