Which of the following poses a threat of combustion in the case of gasoline?

Gasoline poses a significant threat of combustion primarily through its vapors. When gasoline is stored or handled, it tends to evaporate and release vapors into the air. These vapors are highly flammable and can ignite easily in the presence of an ignition source, such as a spark or open flame.

The concentration of these vapors in the air can form explosive mixtures, which is why proper ventilation and safe handling practices are critical when working with gasoline. Vapor pressure plays a key role here; gasoline has a relatively high vapor pressure which means it readily emits vapors that can build up, especially in closed environments.

While liquid gasoline is flammable, it doesn’t ignite as easily as its vapors do. Fumes often refer to the gases emitted from burning materials, and solids do not pose the same level of combustibility as vapors. Thus, understanding the volatile nature of gasoline vapors is crucial for safety in storage and use.