Which term describes a chemical that will ignite spontaneously in air at 54.4 °C or below?

Which term describes a chemical that will ignite spontaneously in air at 54.4 °C or below?

• A. Pyrophoric
• B. Flammable
• C. Explosive
• D. Reactive

Answer: (A)

Pyrophoric substances ignite spontaneously in air. When a chemical will catch fire just by being exposed to air at or below a certain temperature, it’s considered pyrophoric. The threshold of 54.4 °C or below means ignition can occur without an external flame or heat source, simply from contact with air. This is different from flammable materials, which require an ignition source or must reach a specific temperature to burn; it’s also distinct from explosive materials, which release energy rapidly rather than just igniting in air. The term reactive is broad and doesn’t specify spontaneous ignition at a defined temperature, so pyrophoric best fits the scenario.

Pyrophoric substances ignite spontaneously in air. When a chemical will catch fire just by being exposed to air at or below a certain temperature, it’s considered pyrophoric. The threshold of 54.4 °C or below means ignition can occur without an external flame or heat source, simply from contact with air. This is different from flammable materials, which require an ignition source or must reach a specific temperature to burn; it’s also distinct from explosive materials, which release energy rapidly rather than just igniting in air. The term reactive is broad and doesn’t specify spontaneous ignition at a defined temperature, so pyrophoric best fits the scenario.