What is the general formula of alkenes? A. CnH2n B. CnH2n + 2 C. CnH2n – 2 D. CnH2n – 1

The correct answer is A. CnH2n.

Alkenes are hydrocarbons that have a double bond between two carbon atoms. The general formula for alkenes is CnH2n, where n is the number of carbon atoms in the molecule. For example, ethene (C2H4) and ethane (C2H6) are

both alkenes.

Option B is incorrect because it is the general formula for alkanes, which are hydrocarbons that have only single bonds between carbon atoms. Option C

is incorrect because it is the general formula for alkynes, which are hydrocarbons that have a triple bond between two carbon atoms. Option D is incorrect because it is the general formula for cycloalkanes, which are hydrocarbons that have a ring of carbon atoms.