1. Consider each of the following electrode-aqueous solution interface (half-cell), and write the equation for the electrode reaction that occurs first when the potential is moved in (1) a negative direction and (2) a positive direction from the open-circuit potential (OCP). Next to each reaction write the approximate onset potential for the reaction in V vs. NHE. Use Appendix C in the Bard & Faulkner textbook as reference to obtain standard potentials of various possible reactions. Be aware that on Hg electrodes the hydrogen evolution reaction is kinetically slow, as discussed in our lectures. Assume all other possible reactions are kinetically fast and follow thermodynamic predictions. All the cells are at room temperature. (a) Pt/Cd²+ (0.01 M), Fe²+ (0.01 M), H₂SO4 (1 M) (b) Pt/Fe²+ (0.01 M), Fe³+ (0.01 M), H₂SO4 (1 M) (c) Hg/Zn²+ (0.01 M), Ca²+ (0.01 M), HCl (1 M)

Fig: 1