Consider the following reaction.

CO2 (g) + Hz (9) - CO (g) + H2O (1)

What is being oxidized?

carbon

carbon dioxide

oxygen

hydrogen

o

Your hydrogen is being oxidized and your carbon dioxide is being reduced.

Hydrogen

Explanation:

Oxidation and reduction are two types of chemical reactions known as redox reactions. (Red - reduction; ox - oxidation).

A substance is oxidized when it receives an oxygen atom from an oxidizing agent. The substance that receives oxygen is known as a reducing agent.

A substance is reduced when it donates an oxygen atom to another atom. Thus, the substance is known as an oxidizing agent - it supplies oxygen.

In the reaction:

CO2 (g) + Hz (9) - CO (g) + H2O (1)

CO₂ loses oxygen to become CO and H₂ gains oxygen to become H₂O. Thus, CO₂ is an oxidizing agent and H₂ is a reducing agent.