What is Combustion Reaction?

Combustion is the process of burning a carbon compound in the air to produce carbon dioxide, water, heat, and light. Burning is another term for combustion. The majority of carbon compounds burn in the air, producing a great deal of heat. Alkanes, for example, burn in air to produce a lot of heat, making them good fuels. 

Combustion reaction for Carbon Compounds

Consider the burning of methane, a common alkane that is a substantial component of natural gas.

When methane or natural gas is burned in an adequate supply of air, carbon dioxide and water vapour are created, as well as a lot of heat.

CH₄       +          2O₂     →            CO₂         +         2H₂O         +          Heat      +         Light
(Methane)          (Oxygen)        (Carbon dioxide)        (Water)

Methane or natural gas is utilized as a fuel in homes, transportation, and industry because it produces a lot of heat when burned. Butane (C₄H₁₀) is the principal component of the cooking gas (LPG) that we use in our homes. When butane (or LPG) burns in the air in a gas stove’s burner, it produces carbon dioxide and water vapour, as well as a lot of heat and light. Butane or LPG is a great fuel because of this reason.

• Combustion of saturated hydrocarbons– Saturated hydrocarbons, often known as alkanes, burn with a blue, non-sooty flame in the air. This is due to the relatively low proportion of carbon in saturated hydrocarbons, which is totally oxidized by the oxygen in the air. However, if the availability of air and hence oxygen for burning is reduced or limited, even saturated hydrocarbons will undergo incomplete combustion, resulting in a sooty flame and a large amount of black smoke. The gas stoves and kerosene stoves that we use in our homes include tiny holes or inlets for air to ensure that enough oxygen is available for complete fuel combustion and a smokeless blue flame. When the flame of a gas stove turns blue, the fuel has totally burned. When the fuel in a gas or kerosene stove has entirely burned out, leaving a blue flame, the bottom of the cooking utensils is clean from the outside. It does not turn black. In a gas stove, however, if the fuel does not burn fully, a sooty flame is formed, which blackens the bottoms of the cooking utensils from the outside.
• Combustion of unsaturated hydrocarbons– The unsaturated hydrocarbons, also known as alkenes and alkynes, produce black smoke when they burn in the air with a yellow, sooty flame. Ethene and ethyne, for example, emit a sooty flame when burned in the air. Since the percentage of carbon in unsaturated hydrocarbons is higher than that of alkanes, which do not get totally oxidized in the oxygen in the air, they burn with a sooty flame. Air contains only around 21% oxygen, which is insufficient for the full combustion of unsaturated hydrocarbons with high carbon content. Unsaturated hydrocarbons, on the other hand, will burn entirely in pure oxygen, generating a blue flame with no smoke. Acetylene, an ethyne, is an example of an unsaturated hydrocarbon. Because of incomplete combustion, acetylene burns with an extremely sooty flame in the air. The flame produced does not have a high temperature. When acetylene and pure oxygen are combined and burned, the acetylene burns entirely, generating a blue flame.

Hydrocarbons are the most abundant carbon compounds such as alkanes, alkenes, and alkynes. We’ll now discuss some of the chemical properties of hydrocarbons, which are carbon compounds. Combustion reactions, substitution reactions, and addition reactions are the chemical properties that will be discussed here. All types of hydrocarbons (saturated and unsaturated) can be used in combustion reactions, but only saturated hydrocarbons (or alkanes) can be used in substitution reactions, and only unsaturated hydrocarbons can be used in addition reactions (alkenes and alkynes). These reactions are discussed further below.