L4 - pH Curves & Indicators

Polyprotic entities are acids and bases that can lose (or gain) more than one proton. Polyprotic acids can lose more than one proton, and polyprotic bases can gain more than one proton, in Brønsted–Lowry transfers.  Typical pH curves for reactions of diprotic (transfer two protons) or triprotic (transfer three protons) acids and bases differ from those of monoprotic acids and bases—and can provide useful information about the reactions going on.

If more than one proton transfer actually occurs in the course of a titration, chemists believe the process occurs as a series of single-proton transfer reactions.

Lets take a closer look at diprotic and triprotic acids and bases on the next few pages.