Multiple choice

How does carbon dioxide (CO2) help to put off fire?

  1. CO2 is lighter than oxygen. It covers fire like a blanket and cut off the contact between fuel and oxygen.

  2. CO2 is heavier than oxygen. It covers the fire like a blanket and cut off the contact between the fuel and oxygen.

  3. CO2 mixes with O2 and it changes the nature of oxygen which supports burning into non supporting gas.

  4. Carbon dioxide reacts with oxygen gas and thus changes the nature of oxygen, from supporting gas to non supporting gas.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carbon dioxide is heavier than oxygen, so when sprayed on a fire, it settles down and forms a blanket over the burning material. This displaces the oxygen surrounding the fuel, cutting off the oxygen supply needed for combustion. It does not change the nature of oxygen or react with it - it simply physically separates fuel from oxygen.

Keep practicing — related questions