Which element is oxidized, and which is reduced in the following reactions? (a) N21g2 + 3 H21g2¡2 NH31g2

Key Concepts

Oxidation and Reduction

Oxidation and reduction are chemical processes that involve the transfer of electrons between substances. Oxidation refers to the loss of electrons, resulting in an increase in oxidation state, while reduction is the gain of electrons, leading to a decrease in oxidation state. These processes always occur simultaneously in a redox reaction.

Oxidation States

Oxidation states (or oxidation numbers) are assigned to atoms in a compound to indicate their degree of oxidation or reduction. The oxidation state helps in identifying which element is oxidized and which is reduced during a reaction. For example, in the reaction provided, determining the oxidation states of nitrogen and hydrogen will clarify their roles in the electron transfer.

Half-Reactions

Half-reactions are used to separate the oxidation and reduction processes in a redox reaction. Each half-reaction shows either the loss of electrons (oxidation) or the gain of electrons (reduction) for a specific species. Analyzing half-reactions can simplify the identification of which elements are oxidized and reduced in a given reaction.