As a technician in a large pharmaceutical research firm, you need to produce 400. mLmL of a potassium dihydrogen phosphate buffer solution of pHpH = 6.88. The pKapKa of H2PO4−H2PO4− is 7.21. You have the following supplies: 2.00 LL of 1.00 M KH2PO4M KH2PO4 stock solution and 1.50 LL of 1.00 M K2HPO4M K2HPO4 stock solution.
How much 1.00 M KH2PO4M KH2PO4 will you need to make this solution? (Assume additive volumes.)