I've got the following question and I'm having doubts with it:
$$\ce{NAD+ + 2e- + H+ -> NADH}$$
Calculate ${E^\circ}'$ for the half cell $\ce{Pt | NADH, NAD+, H+}$ at pH 7, given that $E^\circ = \pu{-0.358 V}$ at $\pu{298 K}$.
It wants the formal potential. So I write the Nernst equation:
$$E = E^\circ - \frac{RT}{nF}\ln\left(\frac{[\ce{NADH}]}{[\ce{H+}][\ce{NAD+}]}\right)$$
so $$E = E^\circ - \frac {RT} {nF} \ln\left(\frac {1} {[\ce{H+}]}\right) - \frac {RT} {nF} \ln\left(\frac{[\ce{NADH}]}{[\ce{NAD+}]}\right)$$
Now if I understand correctly, $$E^\circ - \frac {RT}{nF} \ln\left(\frac {1} {[\ce{H+}]}\right)$$ is the formal potential, I calculated this and got $\pu{-0.56 V}$. But the literature values are different. Can you help?