What process does hydrogenation refer to in organic chemistry?

Hydrogenation specifically refers to the addition of hydrogen gas to unsaturated hydrocarbons, such as alkenes, resulting in the conversion of these alkenes into saturated hydrocarbons, or alkanes. This process involves the breaking of double bonds in alkenes and the formation of new single bonds with hydrogen atoms. This is commonly utilized in various industrial applications, particularly in the manufacture of vegetable oils into solid or semi-solid fats, such as margarine. By adding hydrogen to the carbon-carbon double bond, the process effectively reduces the level of unsaturation in the molecule, yielding a more stable alkane product. It's important to note that the other options describe different types of reactions.