Some solutes can exist in aqueous solution in more than one form.
Nicotine is an example of such a solute, as are amino acids and other substances that can exist in more than one state of ionization in water. This paper shows how to express the fractional concentrations of the two or more forms in which such substances can be present in an aqueous solution and how to figure out under what conditions any one form will be the major form present. Nicotine serves as the introductory example. Other examples include amino acids and enzymes. All rights reserved.