【Daily Question】Chemical Analysis Edition, 2021.7.1

Choose D. That’s all. Once a fire breaks out, the fire will go out as long as any one of the three basic conditions for combustion (fuel, oxidizer, and an ignition source) is removed. Common fire extinguishing methods include: (1) Isolation method: That is, separating the combustible materials from the source of fire (the fire scene), such as immediately removing flammable items from the fire site. If a gas pipeline catches fire, the valve should be closed immediately to isolate the gas from the source of fire ； (II) Cooling method: This involves reducing the temperature of the burning material below its ignition point, thereby stopping the combustion; for example, water is used to cool down and extinguish the fire ； (III) Asphyxiation method: Preventing oxidizing agents (oxygen, air) from reaching the combustion area, or using inert gases to dilute these oxidizing agents; covering the burning material with sand and similar substances to deprive it of oxygen (or oxidizers), thereby causing the fire to go out ； (IV) Chemical suppression method: Chemical fire extinguishing agents (such as 1211, etc.) are used to stop the combustion reaction.

The conditions for combustion are a combustible material, an oxidizing agent, and temperature. Fire can be extinguished by disrupting the conditions for combustion. The common methods are the three ones in the topic post.