1. The fire extinguisher contains a solution of sodium bicarbonate in water and sulphuric acid in a separate container inside it.
2. When the fire extinguisher is operated by pressing the knob on it, the sulphuric acid gets mixed with sodium bicarbonate solution producing a lot of carbon dioxide gas.
2. When the fire extinguisher is operated by pressing the knob on it, the sulphuric acid gets mixed with sodium bicarbonate solution producing a lot of carbon dioxide gas.
2NaHCO3
+ H2SO4 → Na2SO4
+ 2H2O + 2CO2 ↑
3. Carbon dioxide gas is neither combustible nor helps combustion. It is heavier than air and cuts off the supply of oxygen from air and hence extinguishes the fire.
4. Hence, sodium bicarbonate is used in fire extinguishers.
