5. The glass electrode used in commercial pH meters gives an electrical response proportional to the concentration of hydrogen ion. To convert these responses to a pH reading, the electrode must be calibrated against standard solutions of known H+ concentration. Determine the weight in grams of sodium dihydrogen phosphate (NaH2PO4ƒ| H2O; FW 138) and disodium hydrogen phosphate (Na2HPO4ƒ| H2O; FW 142) needed to prepare 1L of a standard buffer at pH 7.0 with a total phosphate concentration of 0.1 M. pKa of phosphoric acid 6.86.

Question

5.	The glass electrode used in commercial pH meters gives an electrical response proportional to the concentration of hydrogen ion. To convert these responses to a pH reading, the electrode must be calibrated against standard solutions of known H+ concentration. Determine the weight in grams of sodium dihydrogen phosphate (NaH2PO4ƒ| H2O; FW 138) and disodium hydrogen phosphate (Na2HPO4ƒ| H2O; FW 142) needed to prepare 1L of a standard buffer at pH 7.0 with a total phosphate concentration of 0.1 M. pKa of phosphoric acid 6.86.