As a technician in a large pharmaceutical research firm, you need to produce 350. mL of 1.00 M potassium phosphate buffer solution of pH = 7.28. The pKa of H2PO4- is 7.21.
You have the following supplies: 2.00 L of 1.00 M KH2PO4 stock solution, 1.50L of 1.00 M K2HPO4 stock solution, and a carboy of pure distilled H2O.