Hydration is the dissolving of an ionic solid into the water where polar water molecules separate the anions and cations due to ion-dipole attractions.Qualitative analysis of contaminated water supply While the hydroxide ions are kept in solution by their hydrogen bonding with other water molecules, the hydrogen ions, consisting of protons, are immediately attracted to un-ionized water molecules, forming hydronium ions (H 30 +). Hydrogen ions are spontaneously generated in pure water by the dissociation ( ionization) of a small percentage of water molecules into equal numbers of hydrogen (H +) ions and hydroxide (OH –) ions. Furthermore, the two lone pairs on the oxygen in water also contribute to the stabilization of any positively charged ions in solution. This dipole arises from the disparity in electronegativity present in the O-H bonds within the water molecule. The water molecule is polar it has a partial positive charge on the hydrogens while oxygen bears a partial negative charge. The electrically-charged ions undergo ion-dipole interactions with water to overcome strong coulombic attraction, and this produces an aqueous solution.

The key factor that determines solubility is the interaction of the ions with the solvent. This is why it is called the “ heat of hydration.” Hydration of ions is a thermodynamically favorable process, and as such can release heat. To do this, they orient themselves such that they effectively reduce the localized charge on the ions forming dipole ion attractions. In order to dissolve an ionic solid, water molecules must break up the interactions between all of the ions in the solid. This is referred to as a sphere of hydration, or a hydration shell, and serves to keep the particles separated or dispersed in the water. The charges associated with these molecules form hydrogen bonds with water, surrounding the particle with water molecules. Water is therefore referred to as a solvent: a substance capable of dissolving other polar molecules and ionic compounds.

Water is a polar molecule with partially-positive and negative charges, it readily dissolves ions and polar molecules. Hydronium is the common name for the aqueous cation H 3O +, the type of oxonium ion produced by protonation of water. When water is used as the solvent, the dissolving process is called hydration.

Hydonium ion bonding description