A cell potential of 0.427v is measured in an experiment where a solution containing a 0.010 M solution of Pb(NO_3)_2, and a lead electrode is measured relative to a saturated calomel electrode (0.242 v relative to a SHE). The cell potential changes to 0.4861v when the Pb(NO_3)_2 concentration is changed to 1.0 times 10^-4 M. Is this data consistent with the Nernst equation? Enough NaF is now added to the 10^-4 M solution of Pb^2+ to completely precipitate the Pb as PbF_2 and establish an equilibrium concentration of excess F^- equal to 0.190 M The new cell potential is 0.545v. What is the K_sp of PbF_2? From the data in part b), determine the E degree value for the 1/2 cell reaction. PbF_2 +2e- Pb degree +2F^-