What is the purpose of using dry chemical agents in firefighting?

The purpose of using dry chemical agents in firefighting is primarily to smother flames. These agents work by interrupting the chemical reaction of combustion, effectively suffocating the fire. When a dry chemical is deployed, it covers the fuel source and creates a barrier between the fuel and the oxygen in the air. This interference reduces the fire's ability to sustain itself, leading to extinguishment.

Dry chemical agents, such as the commonly used monoammonium phosphate, are particularly effective against various types of fires, including those fueled by flammable liquids and gases. Their ability to quickly suppress flames makes them ideal for emergency situations where rapid response is critical.

Other options, while they may have some relevance in firefighting contexts, do not capture the primary function of dry chemical agents. Cooling hot surfaces typically involves water or other liquid agents. Dispersing vapors is more associated with controlling hazardous substances than extinguishing a fire, and absorbing smoke doesn't directly pertain to extinguishing flames but rather to managing the aftermath of a fire. Thus, the function of dry chemical agents to smother flames is central to their effectiveness in firefighting.