Which statement correctly describes self-reacting solids?

Which statement correctly describes self-reacting solids?

• A. A solid that does not react at all.
• B. Thermally unstable and may decompose exothermically without participation of oxygen.
• C. A material that ignites only when exposed to water.
• D. A liquid that is explosive.

Answer: (D)

Self-reacting solids are materials that can undergo a self-accelerating, exothermic reaction driven by their own internal heat, without needing oxygen from the air. This means they may decompose or react vigorously simply due to thermal instability, producing heat that can feed the reaction even in a closed environment. The statement that best describes this behavior is that the material is thermally unstable and may decompose exothermically without participation of oxygen. That captures the defining feature: self-heating or self-igniting behavior without external oxidizers. The other descriptions aren’t a fit: a solid that doesn’t react at all is the opposite of self-reacting; a material that ignites only when exposed to water involves a specific initiator (water) rather than a self-sustained, air-independent reaction; and describing a liquid explosive introduces a phase change that isn’t consistent with self-reacting solids, which by definition are solids.

Self-reacting solids are materials that can undergo a self-accelerating, exothermic reaction driven by their own internal heat, without needing oxygen from the air. This means they may decompose or react vigorously simply due to thermal instability, producing heat that can feed the reaction even in a closed environment. The statement that best describes this behavior is that the material is thermally unstable and may decompose exothermically without participation of oxygen. That captures the defining feature: self-heating or self-igniting behavior without external oxidizers. The other descriptions aren’t a fit: a solid that doesn’t react at all is the opposite of self-reacting; a material that ignites only when exposed to water involves a specific initiator (water) rather than a self-sustained, air-independent reaction; and describing a liquid explosive introduces a phase change that isn’t consistent with self-reacting solids, which by definition are solids.