Spontaneously combustible materials are described as which property?

Spontaneously combustible materials are described as which property?

• A. A material that is air reactive.
• B. A material that never ignites.
• C. A material that must be cooled before ignition.
• D. A material that ignites only with a spark.

Answer: (A)

Spontaneously combustible materials are defined by their tendency to react with the surrounding air, releasing heat that can cause ignition without an external heat source. This makes them air reactive: the oxidation process in air can build up enough heat to reach ignition temperature on its own if heat isn’t dissipated. That’s why the best description is an air reactive material. The other statements describe different behaviors: some materials won’t ignite at all, some need cooling before ignition (external cooling rather than spontaneous heat buildup), and some only ignite when a spark is present (requiring an outside ignition source, not spontaneous).

Spontaneously combustible materials are defined by their tendency to react with the surrounding air, releasing heat that can cause ignition without an external heat source. This makes them air reactive: the oxidation process in air can build up enough heat to reach ignition temperature on its own if heat isn’t dissipated.

That’s why the best description is an air reactive material. The other statements describe different behaviors: some materials won’t ignite at all, some need cooling before ignition (external cooling rather than spontaneous heat buildup), and some only ignite when a spark is present (requiring an outside ignition source, not spontaneous).