The Ka's for the three acidic protons of phosphoric acid H3PO4 are: 7.11 x 10-3, 6.32 x 10-8, and 4.5 x 10-13. It may be helpful to write out the three dissociation reactions along with their Ka's and pKa's before starting these problems.
1) What is the concentration of K+ in molarity?
2) What is the concentration of OH-?