Explain ion exchange method ?

The water obtained by removing all minerals salts from water is called deionised water.
Hard water is softened by using two types of resins.
1) Cation exchange resin :
Hard water is passed through a tank containing cation exchange resin which consists of giant organic molecules having –COOH or SO₃H
groups.
$\mathrm{RCOOH}+{\mathrm{Ca}}^{2+}\stackrel{ }{\to }(\mathrm{RCOO}{)}_2\mathrm{Ca}+2{\mathrm{H}}^{+}$
$\mathrm{RCOOH}+{\mathrm{Mg}}^{2+}\stackrel{ }{\to }(\mathrm{RCOO}{)}_2\mathrm{Mg}+2{\mathrm{H}}^{+}$
2) Anion exchange resins :
Then water is passed through a tank containing anion exchange resin which consists of giant organic molecule having –NH₃OH.
$\mathrm{R}-\stackrel{+}{N}{H}_3\mathrm{OH}+{\mathrm{Cl}}^{-}\to \mathrm{R}-{\mathrm{NH}}_3\mathrm{Cl}+{\mathrm{OH}}^{-}$
$2\mathrm{R}-\stackrel{+}{N}{H}_3\mathrm{OH}+{\mathrm{SO}}_4^{2-}\to {\left({\mathrm{RNH}}_3\right)}_2{\mathrm{SO}}_4+2{\mathrm{OH}}^{-}$