Hi all. I am working on a general chem "weak acid titration" and I have ran into an issue. When finding the molar mass of a diprotic acid in titration with NaOH, is the moles of OH- the same as the moles of H+ at the equivalence point? Here the equilibrium equations a classmate and I put together:
H
2A + H
2O
HA + H
3O
+HA + H
2O
A
2- + H
3O
+The first equation is Ka
1 and the second is Ka
2. One student recommended that we divide the moles of OH- to find the moles of H+. But when I did this method, my experimental molar mass was completely off the charts and wasn't close to any of the given theoretical diprotic acids. But when I calculate the molar mass with the moles of H+ being the same as OH-, I get a pretty decent experimental molar mass and I found what the unknown could be from the given diprotic acids.
I'm guessing I'm asking if I am using the right method to find the molar mass of the diprotic acid. Thanks!