How is the functional group of alkenes identified?

Alkenes are characterized by the presence of a carbon-carbon double bond (C=C), which is the defining feature of this class of organic compounds. This double bond not only determines the reactivity of alkenes but also influences their physical properties and the types of chemical reactions they can undergo, such as addition reactions.

The presence of the double bond is crucial because it provides alkenes with unsaturation, distinguishing them from alkanes, which contain only single bonds (C-C). The C-H bond, while present in alkenes, is not unique to them and does not define the functional group. Likewise, a carbon-carbon triple bond (C≡C) characterizes alkynes, another class of hydrocarbons, further validating that only the C=C bond is indicative of alkenes.

In summary, identifying the functional group of alkenes relies solely on recognizing the presence of the carbon-carbon double bond, which is essential for understanding their chemical behavior and classification in organic chemistry.