As a technician in a large pharmaceutical research firm, you need to produce 200 mL of 1.00 M a phosphate buffer solution of pH = 7.06. The pKa of H_2PO_4}^- is 7.21. You have 2.00 L of 1.00 M KH_2PO_4 solution and 1.50 L of 1.00 M K_2HPO_4 solution, as well as a carboy of pure distilled H_2O.
How much 1.00 M KH_2PO_4 will you need to make this solution?