Which term defines a material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or initiate combustion of combustible materials?

• A. Peroxide Forming
• B. Oxidizer
• C. Pyrophoric
• D. Disproportionation

Answer: (B)

Oxidizers are substances that supply oxygen or another oxidizing agent to a reaction, so they can promote or initiate combustion of fuels. This means they don’t have to burn themselves—they enable or accelerate burning by providing the oxygen needed for the flame to continue. That direct role in supporting oxidation is what defines them as oxidizers.

Peroxide forming materials describe a tendency to form peroxides upon storage; they’re hazardous because those peroxides can become strong oxidizers, but the term is about peroxide formation risk, not the ongoing readiness to yield oxidizing gas. Pyrophoric materials ignite spontaneously in air, which is about rapid ignition of the material itself, not about supplying oxidizer to other materials. Disproportionation is a redox reaction type where a single species is converted into two species with different oxidation states—again, not the property of acting as an oxidizer.