SQUARE45

Define the standard reduction potentials

E^\text{o}

for two half-reactions:

\text{Ox} + n e^- \rightleftharpoons \text{Red}

and

\text{Ox}' + n' e^- \rightleftharpoons \text{Red}'

. The cell potential

\Delta E

for the reaction

\text{Ox} + \text{Ox}' \rightleftharpoons \text{Red} + \text{Red}'

is given by the difference in these potentials:\n

\Delta E = E^\text{o}(\text{Ox}'/\text{Red}') - E^\text{o}(\text{Ox}/\text{Red}) \quad \text{or} \quad \Delta E = E^\text{o}_{\text{cathode}} - E^\text{o}_{\text{anode}} \quad \text{where } E^\text{o}_{\text{cathode}} > E^\text{o}_{\text{anode}} \text{ for a spontaneous reaction.}

Electrochemical Series