Overview
The reaction Fe3+ + e - = Fe2+ has a reduction potential (E° )of +0.679 V vs. SHE in 1.0 M H2SO4, a standard rate constant (k°) of 1e-06 cm/s, a transfer coefficient (a) of 0.5, and an electrode area of 0.07 cm2. For a solution containing 10 mM Fe3+ and 1 mM Fe2+, calculate the cell potential (Ecell) vs. SHE. Calculate the exchange current density (jo) and describe what is occurring at the electrode surface. Then, use the Tafel equation to calculate the current densities at 0.775 V, 0.825 V, and 0.875 V. Assume the back reaction rate is negligible.