Explain the construction and working of soda acid fire extinguisher. Use diagram and chemical equation to support your answer.
Working of Soda- Acid Fire Extinguisher:
The container of soda acid fire extinguisher holds a sodium bicarbonate solution.
The screw-on cap contains a plunger mechanism which is covered by a safety guard. Below the plunger is a glass phial containing sulphuric acid.
When the plunger is struck, the glass phial is broken and the acid and sodium bicarbonate mix together (observe the diagram given below).
The resulting chemical reaction produces carbon dioxide gas which pressurises the space above the liquid forcing it out through the internal pipe to the nozzle.
The chemical reaction that takes place in the soda-acid fire extinguisher is as follows:
2NaHCO3 + H2SO4 → Na2SO4 + 2H2O + 2CO2