I have a question about using the Nernst equation.
$E = E^\varnothing + (0.059/n)(\log\frac{[Ox]}{[Red]})$
Specifically, I am interested in the reaction of $\ce{MnO4-}$ and $\ce{C2O4^2-}$ below:
$$\ce{2MnO4- + 5C2O4^2- + 16H+ = 2Mn^2+ + 10CO2 + 8H2O}$$
How can I write Nernst equation for $\ce{CO2/C2O4^2-}$ in order to determine the titration curve of this reaction?. I'm confused because $\ce{CO2}$ isn't in the solution, and therefore there isn't a concentration for it.
Is it right if I remove $\ce{CO2}$ from the equation? For example:
$$E = E^\varnothing + \frac{0.059}{2}\left(\log\frac{1}{[\ce{C2O4^{2-}}]}\right)$$