18.0 ml of 0.122 M diprotic acid was titrated with 0.1017 M NaOH. The acid ionization constants for the acid are Ka1 = 5.2*10^-5 and ka2 = 3.4*10^-10. At what added volume of base does the first equivalence point occur?

Question

18.0 ml of 0.122 M diprotic acid  was titrated with 0.1017 M NaOH. The acid ionization constants for the acid are Ka1 = 5.2*10^-5 and ka2 = 3.4*10^-10. At what added volume of base does the first equivalence point occur?

DrBob222 · Answer

H2A + NaOH ==> NaHA + H2O for the first H. NaHA + NaOH ==> Na2A + H2O for the 2nd H. mols H2SO4 = 0.018L x 0.122 M = ? mols NaOH = same for the first H. M NaOH = moles NaOH/L NaOH. Solve for L NaOH.