The Soda-acid fire extinguisher contains
[amp_mcq option1=”sulphuric acid and solution of sodium hydrogencarbonate” option2=”nitric acid and solution of sodium hydrogencarbonate” option3=”sulphuric acid and solution of sodium carbonate” option4=”sulphuric acid and solution of potassium carbonate” correct=”option1″]
This question was previously asked in
UPSC CAPF – 2019
A soda-acid fire extinguisher operates based on the chemical reaction between an acid and a carbonate or bicarbonate to produce carbon dioxide gas. The standard composition of a soda-acid fire extinguisher involves sulphuric acid (H₂SO₄) and a solution of sodium hydrogencarbonate (sodium bicarbonate, NaHCO₃). When the extinguisher is activated (typically by inverting it or breaking a capsule), the acid mixes with the bicarbonate solution, leading to the reaction: H₂SO₄ + 2NaHCO₃ → Na₂SO₄ + 2H₂O + 2CO₂. The released CO₂ gas builds pressure, expelling the solution and also acts as a smothering agent to cut off oxygen supply to the fire.