Question

What does a soda-acid type fire extinguisher contain? How does it work? Explain the working of a soda-acid fire extinguisher with the help of a labelled diagram.

Answer 1

Soda-acid fire extinguishers have a solution of sodium bicarbonate and sulphuric acid housed in separate compartments.

Upon pressing the knob of the fire extinguisher (or inverting it), sulphuric acid reacts with sodium hydrogencarbonate solution, resulting in the production of a substantial amount of carbon dioxide gas. The pressure of the carbon dioxide gas propels a stream of liquid onto the ignited material.

The carbon dioxide gas released alongside the liquid envelops the burning material and obstructs its air supply. When the air supply is interrupted, combustion ceases, and the fire is extinguished. The flow of liquid over the ignited material helps extinguish the fire by cooling the burning substance below its ignition threshold.