Question

In foam type fire extinguisher, which of the following products are formed?
 \[A{l_2}{\left( {S{O_4}} \right)_3} + 6NaHC{O_3}\,\,\,\, \to \,\,\,\,?\]
A. \[\;2Al{\left( {OH} \right)_3} + 6{H_2}O + 3NaS{O_4}\]
B. \[\;2Al{\left( {OH} \right)_3} + 6CO + 3NaS{O_4}\]
C. \[\;2Al{\left( {OH} \right)_3} + 6{O_2} + 3NaS{O_4}\]
D. \[2Al{\left( {OH} \right)_3} + 6C{O_2} + 2Na2S{O_4}\]

Answer 1

Hint: In foam type fire extinguisher, Aluminium sulphate reacts with sodium bicarbonate to which foam stabilizer is added, producing carbon dioxide for fire extinguishing. So, our answer must contain $C{O_2}$. Other than that, the other two compounds in the options are the same.

Complete step by step answer:
Aluminium sulphate reacts with sodium bicarbonate in a foam type extinguisher.
As you all already know, a fire extinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations. There are 5 main types- water, foam, dry powder, $C{O_2}$ and wet chemicals. Fire extinguishers are designed to release a substance that cools the burning material, deprives the flame of oxygen, or interferes with the chemical reactions occurring in the flame.
In this foam extinguisher, aluminium sulphate reacts with sodium bicarbonate to which a foam stabilizer is added, thus producing carbon dioxide for fire extinguishing foams. The carbon dioxide produced cuts off the oxygen supply. And as we already know fire needs oxygen to burn, so $C{O_2}$is effective in extinguishing. Aluminium sulphate is used as a foaming agent in firefighting foam. The reaction is:
 \[A{l_2}{\left( {S{O_4}} \right)_3} + 6NaHC{O_3}\,\,\,\, \to \,\,\,\,2Al{\left( {OH} \right)_3} + 6C{O_2} + 2N{a_2}S{O_4}\]

Thus, option D is the correct answer.

Note:
Fire extinguisher cools down the burning material. Since water cannot be used to extinguish fires caused due to electrical issues, the need for carbon dioxide and foam extinguishers came.