What is the pH of a H2C2O4 solution (c=0.2M) at the 1st and the 2nd equivalence point if it was titrated with 0.2M NaOH? Ka1=5.4*10-2, Ka2=5.4*10-5.
At the 1st point I have to calculate the pH of a HC2O4- solution. pH=(pKa1+pKa2)/2=2.78, but how to calculate the pH for the second point? After the first step the volume of the solution will increase twice so c(HCO4-)=0.1M, here I stopped.