1. Normal salt: It consists of metal ions (including ammonium ions) and nonmetallic ions.

2. Acid salt: It consists of metal ions (including ammonium ions), hydrogen ions and nonmetallic ions.

3. Basic salt: It consists of metal ions (including ammonium ions), hydroxide ions, acidic ions and nonmetallic ions.

Acid radical is an anion formed by combining ordinary hydrochloric acid radical with one or more hydrogen ions.

For example:

Bicarbonate ion (HCO? -): Carbonate ion combines with hydrogen ion, the degree of hydrolysis is greater than that of ionization, and the salt formed with strong alkali is alkaline; Hydrogen sulfate (HSO? -): Sulfate ion combines with hydrogen ion, and the degree of ionization is greater than the degree of hydrolysis. In fact, it is not completely ionized in aqueous solution, but it is considered to be completely ionized in middle school, and the solution formed with strong alkali is acidic; Sulfhydryl ion (HS-): Sulfur ion combines with a hydrogen ion; Monohydrogen phosphate (HPO? 2-): a phosphate ion combines with a hydrogen ion, and basically all salt solutions are soluble in water; Dihydrogen phosphate (h? Po. -): One phosphate ion binds two hydrogen ions and only dissolves potassium, sodium and ammonium.