Question

_______ gas is responsible for combustion.

Answer 1

Hint: Combustion is the process when any substance is burned. Combustion of a substance results in production of heat and energy. The gas that is most abundant will be responsible for combustion. That combustion will be called an aerobic reaction, while in the absence of that gas it is called anaerobic reaction.

Complete answer:
Combustion reaction occurs when a substance or a chemical compound gets burnt. The reaction tends to produce heat, energy and light as products. These products mark that a combustion reaction is exothermic and that it releases energy.
The combustion of any substance happens in the presence of oxygen gas. This is the chief gas responsible to carry out combustion. Without the availability of oxygen the combustion cannot tend to proceed and the reaction will be called incomplete combustion.
The combustion reaction can happen when any hydrocarbon is burnt and produces carbon dioxide and water as:
$C{{H}_{4}}+2{{O}_{2}}\to C{{O}_{2}}+2{{H}_{2}}O+energy$
This reaction is used in making hydrocarbons as a fuel.
Therefore, oxygen gas is responsible for combustion.

Additional information:
The combustion that happens in access of oxygen is termed as aerobic and has carbon dioxide gas produced. But the incomplete combustion happens when there is not enough supply of oxygen, and then it is anaerobic and can result in the formation of carbon monoxide that is a harmful gas.

Note:
The presence of oxygen needed for combustion can be explained through a basic activity. When we burn a candle it readily burns, but when a glass is covered upon a burning candle, the flame gets off, this is due to the removal in the supply of oxygen that a candle turns off. This is also explained, that in case of fire, sand is sprinkled over the place that cuts the supply of oxygen.