Question

For a cell whose potential is -0.46 v with 3 moles of electrons exchanged, what is DG?

Answer 1

ΔG = -nEF

ΔG = Gibbs free energy change
n = moles of electrones participated in
E = Electrode potential
F = Faraday constant

By substituting,
ΔG = -(3 mol) x 96485 A S/ mol x (-0.46) V
      = + 133149.3 J
      = + 133 kJ

Hence the answer is "b".

Since ΔG is a positive value, the reaction is non spontaneous reaction.