Question

Why is equilibrium constant related to E°cell and not to Ecell

Answer 1

As per the Nernst Equation,

Ecell = Eo cell – RT/nF Ln Q

Here Q is the reaction quotient

If we take the value of the equation at the equilibrium then, Ecell = 0, Q = K

0 = Eo cell – RT/nF ln K

Ln K = nFEo cell/RT

Hence, the K constant will be related to the Eo cell but not E cell.

Answer 2

Answer:

You can do this by taking E(cell) = 0 at equilibrium

Explanation:

As per the Nernst Equation,

E(cell) = Eo(cell) – ((RT)/nF(ln Q))

Q - reaction quotient

At equilibrium, E(cell) = 0, Q = K

0 = Eo(cell) – ((RT)/(nF)ln K)

ln K = (n)(F)Eo(cell) / (RT)

Hence, the K constant will be related to the Eo(cell) and not to E(cell)