Final answer:
The correct answer is option 4) Dry powder extinguisher. For fires that involve pool chemicals, a dry powder extinguisher is the correct choice because it can safely extinguish the fire without reacting with the chemicals.
Step-by-step explanation:
Pool chemicals, such as those containing chlorine, can react violently with water, making a water extinguisher unsuitable. Instead, a dry powder extinguisher is recommended because it can interrupt the chemical reaction of the fire without the complication of a water reaction. Carbon dioxide extinguishers are primarily for electrical fires and are not specifically designed for chemical fires, and a foam extinguisher is not suitable for fires involving a reactive chemical like pool chlorine.
Pool chemicals often include oxidizers which may facilitate combustion, and traditional extinguishing agents such as water, foam, or carbon dioxide may not be effective or could exacerbate the situation. A dry powder extinguisher works by smothering and separating the fuel from the oxygen in the air, which helps to put out the fire while also being non-reactive with the chemicals involved.