Question

Carbon dioxide and are most commonly used in fire extinguishers.

• A. water
• B. fuel
• C. air

Answer 1

The correct option is A water

$\bullet$ Water prevents the spreading of fire by lowering down the temperature of a substance. The heat of the fire turns the water into vapours. These vapours cut off the oxygen supply.
$\bullet$ Carbon dioxide $\left({\text{CO}}_2\right)$ is denser than oxygen. When a fire breaks out, it settles over the burning object and forms an air blanket which cuts off the oxygen supply to the burning object. Therefore, it does not support combustion.
$\bullet$ Hence, carbon dioxide and water are most commonly used in fire extinguishers.