Question

In a soda acid fire extinguisher, ______ helps in putting out the fire.
A. \[C{O_2}\]
B. \[C{O_2} + {H_2}O\]
C. \[{H_2}O\]
D. \[{H_2}O + {H_2}\]

Answer 1

Hint: Soda acid fire extinguisher helps in putting out fire by cutting off the supply of air. The scarce supply of oxygen thus puts out the fire.

Complete step by step answer:
A fire extinguisher is a device or a tool that discharges a jet of water, foam, gas, or other materials to extinguish a fire. Fire extinguishers widely help in putting out the fire. The working principle of any fire extinguisher is based on the following three conditions:
> Cooling of the combustible material below the temperature at which it ignites (ignition temperature).
> Cutting off the air supply
> Cooling the combustible material simultaneously with cutting off the air supply.

Soda acid fire extinguisher puts out fire by cutting off the supply of atmospheric oxygen. It is the most effective of all house-hold fire extinguishers. Soda acid fire extinguisher contains sodium bicarbonate and sulphuric acid. It comprises a strong iron vessel with a side discharge nozzle. The iron vessel is loaded with sodium bicarbonate solution. The carbon dioxide is liberated by the action of acid on baking soda, it increases the percentage of carbon dioxide in air as it is a non-supporter of combustion. The chemical reaction involved is:
          $2NaHC{O_3}$+${H_2}S{O_4}$ $\rightarrow$ ${Na_2}S{O_4}$+$2C{O_2}$

The component which helps in putting out fire is carbon dioxide, not water as the supply of air is blocked by the blanket of carbon dioxide.

Hence, the correct answer is (A).

Note:
Remember that soda acid fire extinguishers work by blocking the supply of air. Water doesn’t help in blocking the supply of air, thus it doesn’t help in putting out fire.