addition reaction

In organic chemistry, an addition reaction is an organic reaction in which two or more molecules combine to form a larger molecule called the adduct.

An addition reaction is limited to chemical compounds that have multiple bonds. Examples include a molecule with a carbon–carbon double bond (an alkene) or a triple bond (an alkyne). Another example is a compound that has rings (which are also considered points of unsaturation). A molecule that has carbon—heteroatom double bonds, such as a carbonyl group ( C=O) or imine group (C=N), can undergo an addition reaction because its double-bond.