Q. What is the general formula of alkenes? Answer:
CnH(2n)
Notes: The generic formula for alanes is CnH2n+2, where n is the number identified by the prefix. Alkenes have the formula CnH2N. The general formula means that the number of hydrogen atoms in an alkene is double the number of carbon atoms. For example, ethene is C2H4 and propene is C3H6.