SCH 3U

Conjugate Acid-Base Pairs

According to the Bronsted-Lowry theory every base has a corresponding and every acid has a corresponding .

HCl_(g) + H₂0_(l) -------------> H₃O⁺_(aq) + Cl^-_(aq)

NH_3(g) + H₂O_(l) --------------> NH₄⁺_(aq) + OH^-_(aq)

Some substances (such as water in the above two equations) may behave as and in different circumstances. These substances are said to be .

Strong and Weak Acids and Bases

A solution in which all of the compound is present as ions is called a .

Acids that ionize completely are called .

Acids that only partially ionize are called .

A weak acid dissociate completely into its ions, as a result weak acids will still have some acid in . To indicate that a proportion of the acid still remains in molecular form, a double-headed arrow is used.

Bases that ionize completely are called .

Bases that only partially ionize are called .