Which of the following best describes an explosive?

• A. A substance that slowly decomposes over years.
• B. A substance that rapidly releases energy through a chemical reaction.
• C. A material that cannot ignite under any conditions.
• D. A dense liquid with a high boiling point.

Answer: (B)

Explosives are defined by how quickly they release energy. The best description is a substance that rapidly releases energy through a chemical reaction, because the rapid rate drives a sudden pressure build-up and often a shock wave. Slow decomposition or reactions wouldn’t produce the characteristic high-speed energy release, so they aren’t explosive in the usual sense. A material that cannot ignite under any conditions is not accurate, since many explosives are sensitive to initiation under certain stimuli. A dense liquid with a high boiling point describes a physical property, not the energetic behavior that makes something an explosive.