Question

Which principle is behind the working of fire extinguisher?

• A. The reaction between an acid and a base.
• B. The reaction between an acid and a metal.
• C. The reaction between an acid and a metal bicarbonate.
• D. The reaction between an acid and oxygen.

Answer 1

The correct option is C

The reaction between an acid and a metal bicarbonate.

A fire-extinguisher generally consists of baking soda and vinegar. The role of a fire extinguisher is to extinguish the fire by releasing carbon-dioxide which does not support combustion. So, the reaction which is the principle behind the working of fire extinguisher is the reaction between an acid and a metal bicarbonate. Acids react with a metal bicarbonate to form a metal salt, carbon dioxide gas, and water.

$Acid\left(aq\right)+Metalbicarbonate\left(s\right)\to Metalsalt\left(s\right)+H_{2}O\left(l\right)+C{O}_2\left(g\right)$

Acids react with metals to form a metal salt and hydrogen gas.

$Acid\left(aq\right)+Metal\left(s\right)\to Metalsalt\left(s\right)+H_2\left(g\right)$

Acids react with a base to form a salt and water.

$Acid\left(aq\right)+Base\left(aq\right)\to Salt\left(s\right)+H_{2}O\left(l\right)$

Oxygen is a non-metal and supports combustion. Acids do not react with non-metals.