Calculate the equilibrium constant of the reaction Fe+CuSO4⇌FeSO4+Cu at 25oC Given E0[Fe→Fe2+)=0.44 V and E0(Cu→Cu2+)=−0.337 V.
Given,
Reaction: Fe+CuSO4⇌FeSO4+Cu
Electrode potential ofFe: E0[Fe→Fe2+)=0.44V
Electrode potential ofCu: E0[Fe→Cu2+)=−0.337V
Number of electrons gained or lost, n = 2
Temperature = 25∘C=273+25=298K
In the given reaction, Fe undergoes reduction as it gains two electrons while Cuundergoes oxidation as it loses two electrons.
The cell potential can be calculated as
E0cell=E0reduction−E0oxidation
Substituting the value of electrode potential, we get
E0cell=0.44V−(−0.337V)=0.777V
Now, we know that Gibbs free energy can be given as
ΔG=−n×F×ΔE0 ...(i)
Where n is the number of electrons exchanged, F is Faraday’s constant and ΔE0 is the cell potential.
The relation between Gibbs free energy and equilibrium constant can be given as
ΔG=−R×T×lnK ...(ii)
Where R is the universal gas constant, T is the thermodynamic temperature and K is the equilibrium constant.
Equating (i) and (ii)we get,
−n×F×ΔE0=−R×T×lnK
K can be given as
K=en×F×ΔE0R×T
Substituting the respective values in the above equation for this reaction we get,
K=e2×96485C×0.777V8.3145JK−1mol−1×298K
Simplifying the above expression we get
K=e149937.692477.721
K=e60.5143
Further solving above by logarithmic values, we get
⇒K=1.90×1026
Hence, the equilibrium constant for the given reaction Fe+CuSO4⇌FeSO4+Cu will be K=1.90×1026