
Standard reduction potentials Use the table of standard reduction potentials given above to calculate the equilibrium constant at standard temperature (25 degree C) for the following reaction: Fe(s) + Ni^2+ (aq) rightarrow Fe^2+ (aq) + Ni(s) Express your answer numerically.
Expert Answer
Answer
A)
First, relate Ecell to Keq:
dG = -n*F*Ecell
dG = -R*T*ln(Keq)
where, n is the number of moles, F is farady constant 96500, Ecell, the Eº calcualted , R ideal gas constant, T temperature
solve for Keq
Keq = exp(nF*Ecell/(RT))
We need Eºcell
Eºcell = Ecathode – Eanode = -0.26 – (-0.45) = 0.19 V
now, n = 2 moles of e-
substitute all data:
Keq = exp(nF*Ecell/(RT))
Keq = exp(2*96500*0.19/(8.314*298))
Keq = 2678535.54417
Keq = 2.68*10^6