What is the addition of hydrogen to double or triple bonds known as?

The addition of hydrogen to double or triple bonds is known as hydrogenation. This process involves the addition of hydrogen molecules (H₂) across the unsaturation of alkenes (which have double bonds) or alkynes (which have triple bonds), converting them into saturated hydrocarbons (alkanes). The result is that the unsaturated bonds are replaced with single bonds as hydrogen atoms bond with the carbon atoms.

In organic chemistry, hydrogenation is particularly important because it is used to convert liquid vegetable oils, which contain multiple double bonds, into solid fats. This can improve shelf stability and modify the physical properties of the substances being altered.

Other options involve different chemical processes: oxidation refers to the loss of electrons or an increase in oxidation state, reduction involves gaining electrons or a decrease in oxidation state, and polymerization is the process of reacting monomer molecules together to form a polymer, which does not specifically involve the addition of hydrogen to unsaturated bonds.