The electrochemical processes that occur in the rate limiting step of the corrosion of iron (oxidation of iron) are represented by the half-reactions
Fe2+(aq) + 2e-? Fe(s) Eº = -0.44 V
O2(g) + 4H+(aq) + 4e-= ? 2H2O(l) Eº = 1.23 V
First, write the overall reaction. What is the standard potential for the overall chemical reaction?