Acid-Base Properties of Salt Solutions Salts That Form Neutral Solutions Salts that contain a cation from a strong base AND an anion from a strong acid. e.g.NaCl & Ca(NO 3 ) 2

Salts That Form Acidic Solutions Salts that contain a metal cation (excluding those in Groups 1 & 2) OR a cation that is the conjugate acid of a weak base AND the anion from a strong acid. e.g.NH 4 Cl & Fe(NO 3 ) 3

Salts That Form Basic Solutions Salts that contain a cation from a strong base AND an anion that is the conjugate base of a weak acid. e.g. NaC 2 H3O 2 & Mg(HCO 3 ) 2

Hydrolysis The reaction of an ion with water to produce an acidic or basic solution. e.g.NH 4 + (aq) + H 2 O (l) NH 3 (aq) + H 3 O + (aq) e.g.C 2 H 3 O 2 - (aq) + H 2 O (l) acidic HC 2 H 3 O 2 (aq) + OH - (aq) basic

What Happens if a Salt Has an Acidic Cation and a Basic Cation? e.g.Fe(C 2 H 3 O 2 ) 3 K a for Fe 3+ = 1.5 X K b for C 2 H 3 O 2 - = 5.6 X Since K a > K b, A solution of Fe(C 2 H 3 O 2 ) 3 would be acidic.

What Happens if a Salt Contains an Amphoteric Ion? An amphoteric ion can hydrolyze as an acid OR a base. e.g.HCO 3 -, H 2 PO 4 -, HPO 4 2-, HSO 4 -, etc. If the K a for the ion is > its K b, the ion will act as an acid. If the K b for the ion is > its K a, the ion will act as an acid. e.g.For HCO 3 -, the K a is 4.7 X and its K b is 2.1 X Therefore, this ion will act as a base in water: HCO 3 - (aq) + H 2 O (l) H 2 CO 3 (aq) + OH - (aq) e.g.For HSO 4 -, the K a is 1.0 X and its K b is 1.0 X Therefore, this ion will hydrolyze as an acid in water. HSO 4 - (aq) + H 2 O (l) SO 4 2- (aq) + H 3 O + (aq)