Anode as [product] and cathode as [reactant]?

[EllieSchmidtke_4I]

When calculating K as [product]/[reactant], why would the anode be used as the product and the cathode be used as the reactant?

[Ashley Wang 4G]

Try writing out the oxidation and reduction half reactions for the cell. When you add them together for the overall redox reaction, you will see that the reaction has the cathode species (or concentrations, in a concentration cell) on the reactant side, and anode species/concentrations on the product side. Thus, we apply their concentrations to the Nernst equation.

I hope this is helpful!

[PranaviKolla2B]

Another helpful tip is when looking at the cell diagram, the left side of both the cathode and the anode is the reactants and the right side of both is consequently the products. That is why anode is usually used as the product and cathode as the reactant!

[Brandon Valafar]

If you write out the separate oxidation and reduction reaction then add them together after creating like coefficients for the electrons, you will see that it ends up with the anode being in the products and the cathode being in the reactants.