What is the equilibrium constant for the following reaction at 25°C?

Question

Mg(s) + Zn²⁺(aq) ⇌ Mg²⁺(aq) + Zn(s)

I used the formula: K= e^nFE/RT and I got 6.28 x 10⁵⁴ the homework says that only the exponent is right but not 6.28.

Mg ecell= -2.38

Zn ecell= -0.76

Answer 1

Eºcell = -0.76 + 2.38 = 1.62 V

-RT ln K = -nFEºcell

R = 8.314 J/Kmol

K = equilibrium constant = ?

n = moles electrons = 2

F = Faraday constant = 96,485 C/mol e-

Eºcell = 1.62 V

ln K = nFEºcell / RT

ln K = (2)(96485)(1.62) / (8.314)(298) = 126.2

K = 6.43x10⁵⁴

This is the answer I get.