What is the general formula for alkenes?

Alkenes are unsaturated hydrocarbons characterized by the presence of at least one carbon-carbon double bond. The general formula for alkenes is indeed CnH2n, where 'n' represents the number of carbon atoms in the molecule. This formula reflects that for every 'n' carbon atoms, there are 2n hydrogen atoms, making alkenes distinct from alkanes, which follow the formula CnH2n+2. The absence of the added hydrogen atoms in alkenes (as compared to alkanes) is due to the double bond reducing the number of hydrogen atoms that can bond to the carbons.

In contrast, the other options do not accurately represent the structure of alkenes. The formula CnHn would imply an unusual ratio of hydrogen to carbon that does not conform to organic compound structures. CnH2n+2 represents alkanes, which are saturated and have single bonds only, and CnH2n-2 is characteristic of alkynes, which feature a triple bond between carbon atoms, also indicating a lower proportion of hydrogen. Hence, the formula CnH2n precisely captures the nature of alkenes by accounting for the presence of the double