Which symbol represents the functional group in alkenes?

The functional group in alkenes is represented by the symbol C=C. Alkenes are a class of hydrocarbons characterized by the presence of at least one double bond between carbon atoms. This double bond is crucial in defining the chemical reactivity and properties of alkenes.

When identifying functional groups, a double bond (C=C) indicates unsaturation within the molecule, which allows for additional chemical reactions such as addition reactions. The presence of this functional group differentiates alkenes from alkanes, which contain only single bonds and are therefore saturated.

The other symbols represent different functional groups: -OH is characteristic of alcohols, CHO denotes aldehydes, and -COOH indicates carboxylic acids. Each of these groups has its own specific properties and reactivity, which are distinct from those of alkenes. Thus, recognizing C=C as the functional group is key to understanding the behavior and classification of alkenes within organic chemistry.