Chemistry - Complete s-block Question with Solution | TestHub

Sodium bicarbonate (${\mathrm{NaHCO}}_3$) is commonly used in some types of fire extinguishers. When heated or mixed with an acid, it produces carbon dioxide (${\mathrm{CO}}_2$) gas. Carbon dioxide is denser than air and acts as a fire suppressant by displacing oxygen, thus smothering the flames.

Explanation:

Option 1: ${\mathrm{NaHCO}}_3$ (Sodium bicarbonate) is the correct answer. It is a key component in dry chemical fire extinguishers and some older foam extinguishers. Its decomposition releases ${\mathrm{CO}}_2$, which extinguishes fires.

Option 2: $\mathrm{NaOH}$ (Sodium hydroxide) is a strong base and is not used in fire extinguishers.

Option 3: ${\mathrm{Na}}_2{\mathrm{CO}}_3\cdot 10{\mathrm{H}}_2\mathrm{O}$ (Washing soda or sodium carbonate decahydrate) is not typically used in fire extinguishers.

Option 4: $\mathrm{NaCl}$ (Sodium chloride) is common table salt and has no fire-extinguishing properties.