Question

Phosphoric acid, H3PO4(aq), is a triproticacid, meaning that one molecule of the acid has three acidicprotons. Estimate the pH, and the concentrations of all species ina 0.400 M phosphoric acid solution.

pKa1=2.16

pKa2=7.21

pKa3=12.32

[H3PO4]= ____ M

[H2PO4-] = _____ M

[HPO4 2-] = _____ M

[PO4 3-] = _____ M

[H+] = _____ M

[OH-] = ____ M

pH = ______