For a flammable or combustible liquid, the ___ is the minimum temperature at which the liquid gives off enough vapor to form an ignitable mixture in air.

• A. volatility index
• B. transfer level
• C. flash point
• D. flow rate

Answer: (C)

The flash point is the minimum temperature at which a flammable or combustible liquid gives off enough vapor to form an ignitable mixture in air, provided there is an ignition source present. Above this temperature, the vapor pressure increases so the vapor can mix with air and ignite when sparked or heated. Below it, the vapor concentration is too low to support ignition. This concept helps explain why handling and storage require cooling or shielding from heat to prevent reaching that threshold. Other terms like flow rate or transfer level don’t describe when vapor becomes capable of igniting, and a volatility-related term isn’t the standard measure used for this threshold.