Question

What is the relation between cell potential and equilibrium constant ?​

Answer 1

The Relationship between Cell Potential & the Equilibrium Constant. Thus E°cell is directly proportional to the logarithm of the equilibrium constant. This means that large equilibrium constants correspond to large positive values of E°cell and vice versa.

Answer 2

and the equilibrium constant K, to obtain a relationship between E∘cell and K. Recall that for a general reaction of the type aA+bB→cC+dD, the standard free-energy change and the equilibrium constant are related by the following equation:

ΔG°=−RTlnK(19.5.7)

Given the relationship between the standard free-energy change and the standard cell potential (Equation 19.5.6), we can write

−nFE∘cell=−RTlnK(19.5.8)

Rearranging this equation,

E∘cell=(RTnF)lnK(19.5.9)

For T = 298 K, Equation 19.5.8 can be simplified as follows:

E∘cell=(RTnF)lnK=[[8.314J/(mol⋅K)(298 K)]n[96,485J/(V⋅mol)]]2.303logK=(0.0591 Vn)logK(19.5.10)(19.5.11)(19.5.12)

Thus E∘cell is directly proportional to the logarithm of the equilibrium constant. This means that large equilibrium constants correspond to large positive values of E∘cell and vice versa.