In organic chemistry, a hydration reaction is a chemical reaction in which a hydroxyl group (OH-) and a hydrogen cation (an acidicproton) are added to the two carbon atoms bonded together in the carbon-carbon double bond which makes up an alkene functional group. The reaction usually runs in a strong acidic, aqueous solution. Hydration differs from hydrolysis in that hydrolysis cleaves the non-water component in two. Hydration leaves the non-water component intact.
The general chemical equation of the reaction is the following:
RRC=CH2 in H2O/acid → RRC(-OH)-CH3
In the first step, the acidic proton bonds to the less substituted carbon of the double bond following Markovnikov's rule. In the second step an H2O molecule bonds to the other, more highly substituted carbon. The oxygen atom at this point has three bonds and carries a positive charge. Another water molecule comes along and takes up the extra proton.
Solvation, also sometimes called dissolution, is the process of attraction and association of molecules of a solvent with molecules or ions of a solute. As ions dissolve in a solvent they spread out and become surrounded by solvent molecules.