Acetone has a flash point no more than 140°F. How is it classified?

• A. Combustible liquid
• B. Flammable liquid
• C. Gas
• D. Solid

Answer: (B)

Understanding flash point helps distinguish flammable from combustible liquids. The flash point is the lowest temperature at which the liquid emits enough vapor to form an ignitable mixture. If that point is 140°F or lower, the liquid is classified as flammable. Acetone’s flash point is no more than 140°F, so it meets the criteria for a flammable liquid. It’s a liquid at room temperature with highly volatile vapors, meaning ignition can occur with a relatively low heat source. A combustible liquid would have a flash point higher than 140°F, which doesn’t apply here, and the other options (gas or solid) don’t fit because acetone is a liquid at room temperature.