SCH 4UI - Acid-Base Properties of Salt Solutions
Neutral Salts
NaCl ↔ Na+(aq) + Cl-(aq)
KNO3 ↔ K+ + NO3-
In general these ions form the cations of strong bases and the anions of strong
acids (example – NaOH, HCl, KOH, HNO3)
 Have cations such as Na+ and K+
 Have anions such as Cl-, I-, NO3-, Br-,
Salts that form Acidic Solutions
Two-step reactions:
1) Dissociation reaction:
NH4Cl ↔ NH4+(aq) + Cl-(aq) (remember that Cl-(aq) has no effect)
2) Hydrolysis reaction
NH4+(aq) + H2O(l) ↔
NH3 + H3O+(aq)
base
conjugate acid
Certain metal cations also react to produce acidic solutions.
These metal ions have high charge densities and attract water
molecules to form aqueous hydrated complexes ions. An
example of one of these reactions is shown below:
Al3+(aq) + 6 H2O(l) ↔ Al(H2O)63+ (see the picture to the right)
Metal ions form acids in two-step reactions:
1)
2)
Fe3+(aq) + 6 H2O(l) ↔ Fe(H2O)63+(aq)
Fe(H2O)63+ + H2O(l) ↔ Fe(H2O)5(OH)2+(aq) + H3O+(aq)
acid
conjugate base