1. The problem statement, all variables and given/known data Solid Na2HPO4 is dissolved in water. What is the resulting pH of the solution? Relative pka's of phosphate derivaties are ~2, ~7, and ~12. 2. Relevant equations No equation needed, just look at the species which phosphate would develop. 3. The attempt at a solution I believe the specified compound would be in equilibrium between one of these species; H3PO4, H2PO4 (-), HPO4 (-2) and PO4 (-3). The choices are 12, 7, 2, 9, or there is not enough information.