Question

Use cell potential to calculate an equilibrium constant.

Calculate the cell potential and the equilibrium constant for the following reaction at 298 K:

Cu²⁺(aq) + Hg(l) = Cu(s) + Hg²⁺(aq)

Hint: Carry at least 5 significant figures during intermediate calculations to avoid round off error when taking the antilogarithm.

Equilibrium constant: -------

Answer 1

Hg(l) ---------------> Hg^2+(aq) + 2e^-           E0 = -0.85v

Cu^2+ (aq) + 2e^- ----------> Cu(s)                 E0 = 0.34v

-----------------------------------------------------------------------------

Cu²⁺(aq) + Hg(l) ---------> Cu(s) + Hg²⁺(aq)    E0 cell = -0.51v

     n = 2

   G⁰    = -nEcell*F

                = -2*-0.51*96500

                = 98430J

G⁰      = -RTlnK

98430     = -8.314*298*2.303logK

logK        = -98430/5705.8483

logK        = -17.25

K           = 10^-17.25   = 5.6234*10^-18 >>>>>>answer