Chemistry (Chang), 9th EditionChapter 16:
Acid-Base Equilibria and Solubility EquilibriaChapter Summary1. The common ion effect tends to suppress the ionization of a weak acid or a weak
base. This action can be explained by Le Châtelier’s principle.
2. A buffer solution is a combination of either a weak acid and its weak conjugate
base (supplied by a salt) or a weak base and its weak conjugate acid (supplied by a
salt); the solution reacts with small amounts of added acid or base in such a way
that the pH of the solution remains nearly constant. Buffer systems play a vital role
in maintaining the pH of body fluids.
3. The pH at the equivalence point of an acid-base titration depends on hydrolysis
of the salt formed in the neutralization reaction. For strong acid–strong base
titrations, the pH at the equivalence point is 7; for weak acid–strong base titrations,
the pH at the equivalence point is greater than 7; for strong acid–weak base
titrations, the pH at the equivalence point is less than 7.
4. Acid-base indicators are weak organic acids or bases that change color near the
equivalence point in an acid-base neutralization reaction.
5. The solubility product Ksp expresses the equilibrium between a solid and its ions in solution. Solubility can be found from Ksp and vice versa.
6. The presence of a common ion decreases the solubility of a slightly soluble salt.
7. The solubility of slightly soluble salts containing basic anions increases as the
hydrogen ion concentration increases. The solubility of salts with anions derived
from strong acids is unaffected by pH.
8. Complex ions are formed in solution by the combination of a metal cation with a
Lewis base. The formation constant Kf measures the tendency toward the formation of a specific complex ion. Complex ion formation can increase the solubility of an
insoluble substance.
9. Qualitative analysis is the identification of cations and anions in solution.  | 
