1. The problem statement, all variables and given/known data A mixture of phosphoric acid and NaH2PO4 are titrated against 0.151 M NaOH. The first equivalence point is at 0.00345 L and the second equiv point is at 0.01288 M. The volume of the total mixture was 60 ml. Calculate the concentration of both the phosphoric acid mixtures (H3PO4 and NaH2PO4) 2. Relevant equations H3PO4 + NaOH => NaH2PO4 + H2O 3. The attempt at a solution Iv made the titration graphs and figured out the endpoints (mentioned above). Here's an attempt at the solution... moles H3PO4 = Conc of NaOH x volume of NaOH at 1st eq.point. = 0.151 x 0.00345 = 0.000521 mol moles H2PO4 = conc of NaOH x vol of NaOH at 2nd eq. point = 0.00143 mol Im still unsure and pretty confused... Any help please? Thanks!!