Which statement best defines Reactive as used in chemical safety?

• A. A substance that cools materials to prevent fires.
• B. Undesirable effects such as pressure buildup, temperature increases, or the formation of noxious, toxic or corrosive by products, may occur due to reactions to heating, burning, direct contact with other materials, or other conditions.
• C. A material that cannot react with any other chemical.
• D. A chemical that only reacts in the presence of water to form harmless products.

Answer: (B)

Reactive in chemical safety refers to a substance that can undergo a chemical change under certain conditions (like heating, contact with other materials, or exposure to air or water) and cause hazardous effects such as pressure buildup, heat release, or the formation of toxic, corrosive, or otherwise harmful byproducts. The statement captures this idea by noting that undesirable effects may occur due to reactions triggered by heating, burning, direct contact with other materials, or other conditions, including the potential for pressure and temperature increases and hazardous byproducts. The other options mischaracterize reactivity: one describes a cooling/fire-prevention role rather than reactivity, another describes something inert that cannot react, and another overly restricts reactivity to water with harmless products.