Question

Air is necessary for burning as it supplies oxygen which is essential for burning.
A) True
B) False

Answer 1

Hint: There are three things that are must in proper combination before ignition and combustion can take place: Heat, Oxygen and Fuel. If any of them is missing then combustion will not take place.

Complete answer:
The three things form a Fire Triangle, i.e. For a fire to burn flawlessly there must be efficient availability of fuel, there must be efficient supply of oxygen through air and there must be ignition heat (temperature) to start a continuity in combustion.
There are numerous methods wherein the fire triangle may be damaged or altered. One instance of ways the triangle may be damaged may be carried out with a candle and a jar experiment. Light the candle and set it on a flat surface. After it is burning well, put the jar upside-down on the candle. After sometime, the candle will stop burning. This takes place due to the fact all the oxygen in the jar has been used up via means of the burning candle and no extra oxygen can get to the candle due to the jar. Before you placed the jar over the burning candle, you had all of the components vital for combustion, fuel in the candle and oxygen from the air.
Relight the candle. This time, take a couple of scissors and reduce off the wick underneath the flame and dispose of the candle. Again, the fire will stop after a short duration, this time you had lots of oxygen in the air however you eliminated the fuel.

Therefore, the correct answer is option A. True.

Note: Air in the atmosphere contains about twenty one percent oxygen, and most time fires need at least sixteen percent of oxygen content to combustion. When fuel burns, it reacts with oxygen in the atmosphere from the surrounding air, releasing heat and generating output products like gas, smoke, etc..