How does electronegativity determine hydrogen’s oxidation state in a compound?

The oxidation state of hydrogen in a compound is determined by its electronegativity relative to the element with which it is bonded. Oxidation states are assigned by conceptually distributing shared electrons to the atom that exerts a greater attractive force on them.1

• Positive Oxidation State (+1): When hydrogen bonds with elements that are more electronegative—such as fluorine, oxygen, nitrogen, chlorine, sulfur, or carbon—it is assigned an oxidation state of +1. In these cases, the more electronegative atom is considered to have acquired the shared electrons.1
• Negative Oxidation State (-1): When hydrogen bonds with elements that are less electronegative than itself, such as many metals, it is assigned an oxidation state of -1. These compounds are generally classified as hydrides, where hydrogen effectively acts as the more electronegative component in the bond.12

Because these assignments are based on a formal rule of distributing shared electrons, they provide a consistent method for tracking electron movement in oxidation-reduction reactions, even though they do not necessarily reflect the absolute physical reality of the electron distribution.1