A hypothetical diprotic acid has pKa1=5 and pka2=7. Could a buffer at pH6 be prepared with this acid? If so how?

Answer 1

Using H2CO3 as an example, the pH at the first equivalence point where
H2CO3 ==>H^+ + HCO3^-
H+ at equivalence point is sqrt(k1k2) or
pH = 1/2(pk1+pk2).
Do the same thing with H2A. Simply weigh out the NaHA salt (half neutralized.
pH = 1/2(pK1 + pK2) = 6