What statement defines oxidizing substances?

• A. They absorb oxygen
• B. They supply their own oxygen
• C. They increase the intensity of a fire
• D. They are non-reactive

Answer: (C)

Oxidizing substances are materials that promote oxidation, helping fuels burn more readily by supplying or making oxygen available for the reaction. In a fire context, their presence accelerates combustion and increases how intensely the fire burns. That’s why the statement that best defines oxidizing substances is that they increase the intensity of a fire—they enable more vigorous burning.

Absorbing oxygen isn’t the defining feature, because many oxidizers actively release oxygen or enable oxidation rather than simply taking in ambient oxygen. Saying they always supply their own oxygen isn’t universal either, since not all oxidizers release oxygen in every situation. Being non-reactive is the opposite of what oxidizers do, since oxidizers are by definition reactive and drive oxidation.