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Hydrolysis occurs when salt ions react with water to produce H+ or OH-. Strong acid + strong base salt: no hydrolysis, pH = 7 (NaCl, KNO3). Weak acid + strong base: anion hydrolyses, basic solution (CH3COONa, Na2CO3). pH = 7 + $\frac{1}{2}$pKa + $\frac{1}{2}$log(C). Strong acid + weak base: cation hydrolyses, acidic solution (NH4Cl, FeCl3). pH = 7 - $\frac{1}{2}$pKb - $\frac{1}{2}$log(C). Weak acid + weak base: both ions hydrolyse. pH = 7 + $\frac{1}{2}$pKa - $\frac{1}{2}$pKb, independent of concentration. If Ka > Kb: acidic. If Kb > Ka: basic. If Ka = Kb: neutral (pH = 7). The degree of hydrolysis increases with dilution (similar to Ostwald's dilution law). The weaker the parent acid or base, the greater the hydrolysis of its conjugate ion.