Final answer:
Use a Class B fire extinguisher for liquid fires, not water or a Type A extinguisher. The presence of liquid CO₂ in a fire extinguisher depends on the temperature relative to CO₂'s critical temperature of about 31°C.
Step-by-step explanation:
Never use water or a type A fire extinguisher in an attempt to put out a liquid fire. The correct answer to the question is b) Water. Using water on a liquid fire, such as oil or gasoline, can be extremely dangerous because it can cause the fire to spread. Water is not compatible with these types of fires. Instead, for liquid fires, a Class B fire extinguisher, which is specifically designed for flammable liquids, should be used.
The observations regarding the carbon dioxide fire extinguisher can be explained by understanding the critical temperature of carbon dioxide, which is approximately 31°C. Below this temperature, carbon dioxide can exist as a liquid inside the pressurized extinguisher. However, on a hot day where temperatures exceed the critical temperature, the CO₂ inside the cylinder cannot be liquefied regardless of the pressure, and thus no liquid sloshing is heard.