hydration

…the ions involved are strongly hydrated in solution. In a solution of an aluminum salt, for instance, a proton is transferred from one of the water molecules in the hydration shell to a molecule of solvent water. The resulting hydronium ion (H₃O⁺) accounts for the acidity of the solution:

Hydration of alkynes is unusual in that the initial product, called an enol and characterized by an H―O―C=C― group, is unstable under the conditions of its formation and is converted to an isomer that contains a carbonyl group.

…Group 2 ions are readily hydrated, and the number of water molecules directly attached to a metal ion is greater with the larger ions for purely steric (geometrical) reasons (typically 4, 6, and 6–8 for Be²⁺, Mg²⁺, and Ca²⁺, respectively). The strength of bonding to the water molecules decreases with…

The addition of water (hydration) to the stratum corneum (the outermost layer of skin) greatly enhances the transdermal movement of corticosteroids (anti-inflammatory steroids) and certain other topically applied agents. Hydration can be effected by wrapping the appropriate part of the body with plastic film, thereby facilitating dermal absorption. If…

The total amount of body water is also maintained at fairly constant levels from day to day by the combined action of the central nervous system and the kidneys. If one were to refrain from drinking any water for a few days, the thirst center, located in…

…of the principal mechanisms of hydration of anions in aqueous solution (the bonding of H₂O molecules to the solute species) and hence contributes to the ability of water to act as a good solvent for ionic compounds. It also contributes to the hydration of organic compounds containing oxygen or nitrogen…

…mobile ions keep their primary hydration shell—that is, the water molecules they hold by direct coordination. The more strongly hydrated ions migrate to where there is more water—that is, out of the resin and into the surrounding solution.

This process is called hydration. The hydration of its ions tends to cause a salt to break apart (dissolve) in the water. In the dissolving process the strong forces present between the positive and negative ions of the solid are replaced by strong water-ion interactions.