# As a technician in a large pharmaceutical research firm, you need to produce 400. mL of 1.00 M potassium phosphate buffer solution of pH = 7.05. The pKa of H2PO4− is 7.21.You have the following supplies: 2.00 L of 1.00 M KH2PO4 stock solution, 1.50 L of 1.00 M K2HPO4 stock solution, and a carboy of pure distilled H2O.How much 1.00 M KH2PO4 will you need to make this solution?

Question

As a technician in a large pharmaceutical research firm, you need to produce 400. mL of 1.00 M potassium phosphate buffer solution of pH = 7.05. The pKa of H2PO4− is 7.21.
You have the following supplies: 2.00 L of 1.00 M KH2PO4 stock solution, 1.50 L of 1.00 M K2HPO4 stock solution, and a carboy of pure distilled H2O.
How much 1.00 M KH2PO4 will you need to make this solution?