Which type of reaction would be expected if a molecule undergoes both addition and oxidation?

The process described involves both addition and oxidation, which are key characteristics of hydroxylation reactions. Hydroxylation is a type of reaction where hydroxyl groups (-OH) are added to a molecule, typically as a result of an addition reaction. This can occur in the context of alkenes, where the alkene undergoes an addition reaction of water in the presence of a catalyst, leading to the formation of alcohols.

Moreover, hydroxylation often involves the oxidation of the original compound, transforming a double bond into an alcohol group. The transformation means that it not only adds hydroxyl groups but also can change the oxidation state of the molecule, which aligns well with the concept of oxidation.

In contrast, other types of reactions, such as hydrogenation, primarily focus on the addition of hydrogen (rather than hydroxyl groups) to a double bond and do not involve oxidation. Substitution reactions involve replacing one atom or group in a molecule with another without adding new functional groups, while elimination reactions typically result in the removal of atoms or groups, thereby reducing the overall number of bonds in a compound rather than adding new ones.

Thus, the characteristics and outcomes of hydroxylation align perfectly with the requirements of the question regarding addition and oxidation.