Interaction of `H^(+) and OH^(-)` with the anion and the cation of a salt respectively original acid and the original base is called hydrolysis. For example,
`underset("Salt")(Na_(2)CO_(3)) + 2H_(2)O to underset("Base")(2NaOH)+ underset("Acid")(H_(2)CO_(3))`
Hydration, on the other hand, means addition of `H_(2)O` to ions or molecules to form hydrated ions on hydrated salts. For example,
`underset("Salt")(Na^(+)Cl^(-)(s)) + H_(2)O(l) to Na^(+)(aq) + Cl^(-)(aq)`
`underset("Colourless")(CuSO_(4)(s)) + 5H_(2)O(l) to underset("(Blue)")(CuSO_(4).5H_(2)O(s))`
