What is the general formula for alkenes?

The general formula for alkenes is represented as CnH2n, where "n" stands for the number of carbon atoms in the alkene molecule. This formula indicates that for every carbon atom present, there are twice as many hydrogen atoms, minus the two hydrogen atoms that are replaced by a double bond between two carbon atoms.

Alkenes are characterized by having at least one carbon-carbon double bond, which leads to the reduction in the number of hydrogen atoms compared to alkanes, which follow the formula CnH2n+2. The presence of this double bond is what differentiates them from saturated hydrocarbons. The formula CnH2n thus reflects that all alkene molecules will include this structural feature, confirming their identity as unsaturated hydrocarbons.

The other choices provided do not accurately represent alkenes. For instance, CnH2n-2 suggests an even lower proportion of hydrogen, which would relate to alkynes that contain triple bonds, while CnH2n+2 describes the saturated alkanes. CnH2n-1 does not align with the structural characteristics of alkenes either. Therefore, the choice of CnH2n is an accurate depiction