What is the extinguishing agent that is an aqueous solution of potassium carbonate?

The correct answer is wet chemical, which is specifically designed to combat fires involving cooking oils and fats, commonly found in commercial kitchens. Wet chemical fire extinguishers work by creating a thin layer of foam that effectively cools the flames and eliminates the ability for the fire to reignite, while also suppressing the chemical reaction that maintains the fire. The aqueous solution of potassium carbonate serves as the active ingredient that reacts with the burning oils, helping to extinguish the fire.

In scenarios where grease fires occur, wet chemicals are preferred because they can specifically target the combustion processes unique to that type of fire. The formulation permits a controlled reaction that mitigates the risk of flare-ups while ensuring safety for the user.