# Positive electrode of an electrochemical cell?

I had the following problem:

Relevant information from Data Book:

$\ce{Ag+ + e- <=> Ag}$

$E^0 = +0.80$

and

$\ce{Fe^3+ + e^- <=> Fe^2+}$

$E^0 = +0.77$

This means $E_\mathrm{cell}$ is +0.03. (right)

And (I thought) that the left ($\ce{Fe}$) half cell has the positive electrode/anode as the ions lose electrons to the anode. I thought that the half equation with the more positive $E^0$ value went forwards.

However this is wrong. Where did I go wrong in my reasoning?

• Your reasoning was correct, except for the part that Fe is positive electrode. As $Fe^{2+}$ lose electron, it produce electron, so that the electrode becomes negative. Ag electrode becomes negative for the same reason. – Huy Ngo Feb 7 '17 at 15:07

Ecell = (Ereduction)cathode - (Ereduction)anode