Required Correct Answer:

(a) CO₂

Explanation:

CO₂ is a dense gas that is used in fire extinguishers. When used, it forms a blanket that displaces the oxygen from near the fire. That is, a layer of carbon dioxide is formed between the fire and the oxygen. As oxygen level decreases, the combustion process decreases, and the flame ultimately dies. This extinguisher is usually used at times of electric fires.

Hence the required answer is option A.

What is a fire extinguisher?

As the name, suggests, a fire extinguisher is an instrument that helps to extinguish fire. Not all extinguishers are CO₂ extinguishers. CO₂ extinguishers are used in cases of electric fires. Other extinguishers include water, soda-acid extinguisher etc.

Extinguishers help to cut off the air supply, one among the three techniques to stop a fire.

Exploring the other options:

(b) SO₂

SO₂ has no role to play in the process of combustion. It is an acidic gas that triggers environmental pollution as it combines with water in the air and rains down as acid rain. Acid rain is harmful for both living and non-living organisms. This gas is emitted by industries, refineries and when we burn fossil fuels.

(c) NO₂

NO₂ also has no role to play in the process of combustion. It also causes acid rain as it forms nitric acid when combined with water.

(d) H₂S

H₂S is a very highly inflammable as well as poisonous. It has a foul smell of rotten eggs. It is used to make sulphur and can cause hazardous effects when breathed. When it is burned, SO₂ gas is evolved.

Verified answer

Answer:

The correct answer is CO2 (a)

Explanation:

Carbon dioxide is a compressed gas agent that prevents combustion by displacing the oxygen in the air surrounding the fire. The two types of dry chemical extinguishers include one that contains ordinary sodium potassium bicarbonate, urea potassium bicarbonate, and potassium chloride base agents.

Hope this answer helps you out.