What is the general formula for alkenes?

What is the general formula for alkenes?

• A. CnH2n
• B. CnH2n + 2
• C. CnH2n - 2
• D. CnH2n + 1

Answer: (A)

The general formula for alkenes is represented as CnH2n. This formula indicates that for every 'n' carbon atoms present in the molecule, there are '2n' hydrogen atoms. Alkenes are a class of hydrocarbons that contain at least one carbon-carbon double bond (C=C). This double bond is what characterizes alkenes and distinguishes them from alkanes, which have only single bonds and follow the formula CnH2n+2. In the case of alkenes, the double bond allows for fewer hydrogen atoms compared to alkanes, which explains why the formula is CnH2n rather than CnH2n+2. Thus, for any given number of carbon atoms n, the corresponding number of hydrogen atoms is calculated simply by doubling n. For example, if there are 2 carbon atoms (n=2), the number of hydrogen atoms would be 2*2 = 4, resulting in the molecule ethene (C2H4). Other formulas in the choices provided do not accurately reflect the structure of alkenes. For instance, CnH2n+2 applies to alkanes, while CnH2n-2 and C

The general formula for alkenes is represented as CnH2n. This formula indicates that for every 'n' carbon atoms present in the molecule, there are '2n' hydrogen atoms. Alkenes are a class of hydrocarbons that contain at least one carbon-carbon double bond (C=C). This double bond is what characterizes alkenes and distinguishes them from alkanes, which have only single bonds and follow the formula CnH2n+2.

In the case of alkenes, the double bond allows for fewer hydrogen atoms compared to alkanes, which explains why the formula is CnH2n rather than CnH2n+2. Thus, for any given number of carbon atoms n, the corresponding number of hydrogen atoms is calculated simply by doubling n. For example, if there are 2 carbon atoms (n=2), the number of hydrogen atoms would be 2*2 = 4, resulting in the molecule ethene (C2H4).

Other formulas in the choices provided do not accurately reflect the structure of alkenes. For instance, CnH2n+2 applies to alkanes, while CnH2n-2 and C