Some h2po4 and hpo42- are added to water such that both concentrations are 5.25 mm (pkg = 2.1, 6.8, 12.4). the water was initially at ph 6.65 and 25.0 °c. how does the ph of the solution change as the reaction approaches equilibrium? o the ph will decrease o the ph will remain unchanged o the ph will increase o there is insufficient information to answer this question