Chemistry
Abir went to a mall with his parents on Sunday. While walking around, he noticed red devices fixed on the walls at different places. Curious, he asked his mother about them. His mother explained that those are fire extinguishers. They help to put out fires by releasing a special gas.
His father also told him that it is now mandatory to install fire extinguishers in all kinds of buildings such as offices, schools, apartments, hospitals, etc. to keep people safe.
(a) Name the gas released by fire extinguishers to put out fires.
(b) How does this gas work in putting out the fire ?
(c) Name the type of fire extinguishers used for (i) oil fire (ii) electrical fire.
(d) Why is it dangerous to use water on electrical fire ?
Answer
(a) The gas released by fire extinguishers is carbon dioxide.
(b) Carbon dioxide helps to put out fire by:
- Cutting off oxygen supply as fire needs oxygen to burn.
- Forming a blanket over the fire, which prevents further burning.
(c) Types of fire extinguishers used are:
(i) Oil fire: Foam fire extinguisher
(ii) Electrical fire: Carbon dioxide fire extinguisher
(d) It is dangerous to use water on an electrical fire because of the following reasons:
- Water is a good conductor of electricity.
- It can cause electric shock to the person using it.
- It may also spread the fire if live current is present.
Related Questions
Match the following:
Column A Column B A product of incomplete burning Hopcolite Nature of carbon monoxide Combustible gas A compound formed by the combination of haemoglobin and carbon monoxide Carboxyhaemoglobin A mixture of metallic oxides Carbon monoxide Carbon monoxide Highly poisonous Explain the poisonous nature of carbon monoxide.
Why is carbon monoxide called the silent killer?
Explain the reducing action of carbon monoxide with a suitable example.