Phosphoric acid is a triprotic acid with the following pKavalues:
pKa1=2.148 pKa2=7.198 pKa3=12.375
You wish to prepare 1.000 L of a 0.0200 M phosphate buffer at pH7.720. To do this, you choose to mix the two salt forms involved inthe second ionization, NaH2PO4 and Na2HPO4, in a 1.000 L volumetricflask and add water to the mark. What mass of each salt will youadd to the mixture?
mass NaH2PO4= ________g mass Na2HPO4= __________g
What other combination of phosphoric acid and/or its salts couldbe mixed to prepare this buffer? (Check all that apply).
H3PO4 and NaH2PO4
H3PO4 AND Na2HPO4
H3PO4 and Na3PO4
NaH2PO4 and Na3PO4
Na2HPO4 and Na3PO4
