14. Ampholytes - Amphoteric Species

Some species can react as an acid and as a base. This is the case for negative ions of polyprotic acids still containing hydrogen (NaHCO₃ for instance):

This is also the case for aminoacids (Glycine, H₂N-CH₂-COOH for instance), containing an acidic (-COOH) and a basic (-NH₂) group:

The pH of a solution of an ampholyte can be calculated, fairly accurate, by using the approximate formula:

Note that the pH of a solution of an ampholyte is independent of the concentration.

Summary

Ampholytes

Species that can react as an acid and as a base. Negative ions of polyprotic acids still containing hydrogen / Aminoacids