Which statement about flammable liquids and their vapors is accurate?

• A. They can produce ignitable vapors at room temperature
• B. They always boil at high temperatures
• C. They cannot form vapors
• D. They are always solids at room temperature

Answer: (A)

Flammable liquids release vapors that can ignite when mixed with air, even at room temperature. The important idea is that many of these liquids have enough vapor pressure at ambient conditions to produce vapors that can reach the flammable range, so an ignition source could cause a flame. This is why a liquid with a low flash point is a hazard in normal environments: its vapors can be ignitable without heating.

So, statements about vapors being ignitable at room temperature are accurate because evaporation supplies the combustible vapor without needing to boil. The other ideas aren’t correct because flammable liquids can vaporize (not just boil), they are not restricted to forming vapors only at high temperatures, and they are not necessarily solids at room temperature.