I had a look at an online page for redox titrations (http://www.titrations.info/potentiometric-titration-equivalence-point-calculation). I can extend my understanding of that page far enough to say that for two half-reactions v_{A} A + v_{e1} e^{-} ⇔ v_{B} B (v_{Species} is the stoichiometric coefficient) and v_{C} C + v_{e2} e^{-} ⇔ v_{D} D, the point at which [A] = v_{A}/v_{D} * [D] and [ B] = v_{B}/v_{C} * [C] is the equivalence point. However, what is the definition of the redox equivalence point if we instead have the following reactions occurring: v_{A} A + v_{B} B +...+ v_{e1} e^{-} ⇔ v_{C} C + v_{D} D and v_{E} E + v_{F} F +...+ v_{e2} e^{-} ⇔ v_{G} G + v_{H} H And how, in these cases, can we calculate the potential at the equivalence point? (The linked web-page only goes through a more basic case.)