What occurs during complete combustion of alkanes?

During the complete combustion of alkanes, the primary reaction involves the alkane reacting with oxygen to produce carbon dioxide and water. This process is characterized by the combustion of hydrocarbons in the presence of a sufficient supply of oxygen.

When an alkane, which consists of carbon and hydrogen, combusts completely, every carbon atom in the alkane combines with oxygen to form carbon dioxide. Similarly, the hydrogen atoms bond with oxygen to produce water. The general reaction can be summarized as follows:

[ \text{C}n\text{H}{2n+2} + (3n+1)O_2 \rightarrow nCO_2 + (n+1)H_2O ]

This reaction is exothermic, meaning it releases energy in the form of heat and light, which is why alkanes are often used as fuels.

The other choices do not reflect the complete combustion of alkanes: forming carbon monoxide indicates incomplete combustion, forming ethanol suggests a different reaction involving a different pathway of organic chemistry, and producing methane and oxygen is not a combustion reaction at all. Thus, the formation of carbon dioxide and water accurately describes the complete combustion process for alkanes.