The Ka values of H3PO4 are shown below.

Question

Ka1 7.5 10-3
Ka2 6.2 10-8
Ka3 4.8 10-13

What is the pH of a 0.19 M solution of NaH2PO4?

Answer 1

The pH at the first equivalence point of in the titration of H3PO4 is determined by the hydrolysis of the salt, NaH2PO4.
(H^+) = sqrt(k1k2).

Answer 2

nnb