strength of acids and bases

In chemistry, the ability of acids and bases to dissociate in solution with water, and hence to produce a low or high pH, respectively.

A strong acid is fully dissociated in aqueous solution, whereas a weak acid is only partly dissociated. Since the dissociation of acids generates hydrogen ions, a solution of a strong acid will have a high concentration of hydrogen ions and therefore a low pH. A strong base will have a high pH, whereas a weaker base will not dissociate completely and will have a pH of nearer 7.

For a weak acid or base, the ease of dissociation, and hence strength, is given by its dissociation constant.