0.050 mol of K2HPO4 was dissolved in about 800mL of water, as well as the pH was adjusted to 7.0 using a standardized pH meter and a 1 M H3PO4 solution, followed by addition of water to a volume of 1.00 L. Show that 22mL of 1 M H3PO4 solution were added? Utilize charge and mass balance
The relevant Ka's for probably relevant phosphate species are
H3PO4 H2PO4- + H+ K1 = 7 X 10-3
H2PO4-HPO4-2 + H+ K2 = 6.2 X 10-8
HPO4-2 PO4-3 + H+ K3 = 4.5 X 10-13