Cation Exchangers:

A broad variety of cation exchangers along with fixed ionic groups of different character and different acid strength are commercially available. The most general of these are strong-acid resins with (SO₃^-) and weak acid resins with carboxylic acid groups (-COO^-). Even if we consider these two types of resins, the resins of several strength could be made since dissociation constants are affected by the nature and configuration of the units to that the groups are attached. The arylsulphonic acids are stronger than alkylsulphonic acids. Several ion exchangers contain two or more different kinds of ionic groups and they are known as bifunctional or polyfunctional.