This was a question in my half yearlies:

A solution of KH2PO4 contains the ion H2PO4-. H2PO4- is an amphiprotic substance, yet in solution, the pH is greater than 7. With relevant equations, explain why.

This is what I wrote:

H2PO4- has 2 equations, one acting as acid (donates H+), one acting as base (accepts H+)

Then I wrote equations for H2PO4- with water for acid, and showed that it produces HPO4 2-, and then another set of equations for HPO4 2-, showing that it produces both H2PO4- and PO4 3-. This means that there is a buffer effect in the second set of equations, so the acid-equation for H2PO4- does not contribute to changing pH.

Then I wrote H2PO4- with base, and showed that it produced H3PO4 and OH-. Since H3PO4- is not amphiprotic, then the final pH will be greater than 7 due to the OH- ion.

So...Am I right or wrong? =(