Hydration reaction
![](/Images/godic/202501/19/Hydrationreaction4551.png")
![CuSO4·5H2O is bright blue and has a rather different structure from its colourless anhydrous derivative.](/Images/godic/202501/19/Copper_sulfate4552.jpg")
![Anhydrous CuSO4 powder.](/Images/godic/202501/19/Copper_sulfate_anhydrous4552.jpg")
In chemistry, a hydration reaction is a chemical reaction in which a substance combines with water. In organic chemistry, water is added to an unsaturated substrate, which is usually an alkene or an alkyne. This type of reaction is employed industrially to produce ethanol, isopropanol, and 2-butanol.