Question

Which of the following chemicals are present in a carbon dioxide fire extinguisher?

• A. Calcium carbonate
• B. Sodium bicarbonte
• C. Hydrochloric acid
• D. Sulphuric acid

Answer 1

Answer: (B), (D)

The correct options are
B Sodium bicarbonte
D Sulphuric acid

A carbon dioxide fire extinguisher contains sodium bicarbonate and sulphuric acid, which reacts to produce carbon dioxide gas.
The reaction takes place as shown below.

$2{\mathrm{NaHCO}}_3\left(s\right)+H_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+2{\mathrm{CO}}_2\left(g\right)+2H_{2}O\left(g\right)\mathrm{Sodium}\mathrm{Sulphuric}\mathrm{Sodium}\mathrm{Carbon}\mathrm{Water}\mathrm{bicarbonate}\mathrm{acid}\mathrm{sulphate}\mathrm{dioxide}$


Carbon dioxide is more dense than the air. Thus, it forms a blanket over the fire, cutting off the supply of oxygen from air. This helps in extinguishing the fire.