How can adding hydrogen atoms reduce an organic compound?

Adding hydrogen atoms to an organic compound can reduce it by increasing the electron density associated with a carbon atom. This process is known as reduction, where a substance gains electrons.12

In organic chemistry, reduction commonly occurs when hydrogen atoms are added to a carbon atom, or when oxygen atoms are removed from a carbon atom. For instance, the addition of two hydrogen atoms to a carbonyl group results in the formation of an alcohol, which is a type of reduction.345

Hydrogenation is a specific type of chemical reaction where molecular hydrogen is added to an element or compound, often in the presence of a catalyst. This can involve hydrogen adding to double or triple bonds within a molecule, or it can lead to the breaking apart of the molecule (hydrogenolysis). This process is crucial in various industrial applications, such as the production of edible fats and in the petroleum industry for manufacturing gasoline and petrochemicals. Common catalysts for hydrogenation include metals like nickel, platinum, and palladium.6