Explosives are classified as high or low explosives based on their detonation velocity.

• A. Detonation velocity
• B. Temperature
• C. Molar mass
• D. Heat of formation

Answer: (D)

The key factor is detonation velocity—the speed at which the detonation wave travels through the material. High explosives support a true detonation with a fast, shock-front propagation, producing an instantaneous, powerful blast. Low explosives, by contrast, burn rapidly in a deflagration and propagate much more slowly, often requiring confinement to initiate any detonation. This difference in how quickly the reaction front moves is what defines high versus low explosives, not how hot they burn, their molar mass, or their heat of formation. Those other properties influence energy release and behavior, but they do not determine the classification.