You should have learned how to
calculate the pH of a solution containing as
solute, using the
Ka e×pression and the initial concentrations of the members of the conjugate pair.
- a single substance which is only acidic or only basic OR
- two substances, an acid and its conjugate base
| Ka = | [conjugate base][H3O+] |
| [acid] |
Ka unknown, and [H3O+] (pH) given or
Ka given, and [H3O+] (pH) unknown
Problems have either :
Therefore, to obtain the desired result it is necessary to substitute for [conjugate base] or [acid].
The reasoning used to make these substitutions is outlined on the next page.