Question

Explain, with the help of a labelled diagram, how a soda-acid type fire extinguisher works.

Answer 1

A soda-acid type fire extinguisher contains concentrated solution of sodium hydrogen carbonate (NaHCO₃) in a small cylinder fitted with a glass bottle filled with sulphuric acid. When fire breaks out, the cylinder is hit on a hard surface to break the bottle. Once the bottle breaks, the acid reacts with sodium hydrogen carbonate to evolve carbon dioxide and water in the form of vapours. Carbon dioxide, being a non-supporter of combustion, forms a blanket over the fire and extinguishes it. Water, because of its cooling effect, brings down the temperature below the ignition temperature to check burning.