include NaOH (sodium hydroxide), KOH (potassium hydroxide), and other soluble hydroxides of
Group IA and IIA metals. Calculation of the pH and pOH of strong acids and bases assumes complete
dissociation of the acid or base in solution: [H+] = normality of strong acid and [OH−] = normality of
strong base.
WEAK ACIDS AND BASES
Weak acids and bases are those that only partially dissociate in aqueous solution. A weak
monoprotic acid, HA, in aqueous solution will achieve the following equilibrium after dissociation:
HA (aq) + H 2 O (l) H 3 O+ (aq) + A− (aq)BASIC CONCEPT
Weak acids and gases only partially dissociate in aqueous solution.The acid dissociation constant, Ka, is a measure of the degree to which an acid dissociates.
The weaker the acid, the smaller the Ka. Weak acids have values of Ka that are much smaller than 1.
Note that Ka, like other equilibrium constants, does not contain an expression for the pure liquid,
water. Many weak acids are organic compounds.
A weak base, BOH, undergoes dissociation to give B+ and OH−. The base dissociation constant, Kb, is
a measure of the degree to which a base dissociates. The weaker the base, the smaller its Kb. For a
monovalent base, Kb is defined as follows: