Key Concepts

• The standard electrode potential for a redox reaction, E^o_(redox), is the sum of the standard electrode potential for the oxidation reaction, E^o_(oxidation), and the standard electrode potential for the reduction reaction, E^o_(reduction):
  E^o_(redox) = E^o_(oxidation) + E^o_(reduction)

• Calculating E^o_(redox) for a redox reaction:
  X + Y⁺ → X⁺ + Y

1. Write the two balanced half-reaction equations
   reduction : Y⁺ + e^- → Y
   oxidation : X → X⁺ + e^-

2. Use tabulated values to find the standard electrode potential for each half-equation:
   Y⁺+e^- → Y   E^o_{(reduction of Y⁺)}
   X → X⁺+e^-   E^o_{(oxidation of X⁺)}
   (Note: E^o_(oxidation) = -E^o_(reduction))

3. Add the two half-reaction equations together, and add together their standard electrode potentials:
   Y⁺+e^- → Y   E^o_{(reduction of Y⁺)}
   X → X⁺+e^-   E^o_{(oxidation of X⁺)}
   

   ---

   
   Y⁺+X → Y+X⁺

   E^o_(redox) = E^o_{(reduction of Y⁺)} + E^o_{(oxidation of X⁺)}

   Note: changing the stoichiometric coefficients for reactions and products when balancing a redox reaction equation does not change the value of E^o for either the oxidation or the reduction reaction.