Types of salt

Salts can be classified into the following types:

a) Normal salt

A salt that does not contain any replaceable hydrogen ions is a normal salt. It is obtained by replacing all the hydrogen ions of an acid by metal ions or ammonium ions. Examples: NaCl, Na₂SO₄, Na₃PO₄, NH₄Cl, K₂CO₃, CuSO₄ etc.

b) Bisalts or Acid salts

A bisalt, or an acid salt contains replaceable hydrogen ions in association with the acidic radicals. It is obtained by the incomplete replacement of hydrogen ions by metal ions or ammonium ions.

Examples: NaHCO₃, NaH₂PO₄ and Na₂HPO₄.

Since such salts also contain hydrogen ion, the term 'bi' or acid can be substituted by hydrogen, e.g. sodium bicarbonate or sodium acid carbonate is also called sodium hydrogen carbonate.

When bisalts or acid salts dissociate in water, they yield hydrogen or hydronium ions.