Which of the following is the correct general formula for alkenes?

Which of the following is the correct general formula for alkenes?

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

Answer: (A)

The correct general formula for alkenes, which are hydrocarbons containing at least one carbon-carbon double bond, is indeed represented by the formula CnH2n. This formula indicates that for every n number of carbon atoms, there are 2n hydrogen atoms. Alkenes have this specific formula because they are unsaturated compounds; the presence of a double bond reduces the number of hydrogen atoms that can attach to the carbon framework compared to alkanes, which follow the formula CnH2n+2. Thus, alkenes can accommodate fewer hydrogen atoms than alkanes, leading to their formula being CnH2n. This also helps distinguish alkenes from other types of hydrocarbons like alkynes, which have a triple bond and follow a different formula (CnH2n-2), and that signifies even more unsaturation. Understanding these distinctions is crucial for accurately determining the structure and behavior of organic compounds.

The correct general formula for alkenes, which are hydrocarbons containing at least one carbon-carbon double bond, is indeed represented by the formula CnH2n. This formula indicates that for every n number of carbon atoms, there are 2n hydrogen atoms.

Alkenes have this specific formula because they are unsaturated compounds; the presence of a double bond reduces the number of hydrogen atoms that can attach to the carbon framework compared to alkanes, which follow the formula CnH2n+2. Thus, alkenes can accommodate fewer hydrogen atoms than alkanes, leading to their formula being CnH2n.

This also helps distinguish alkenes from other types of hydrocarbons like alkynes, which have a triple bond and follow a different formula (CnH2n-2), and that signifies even more unsaturation. Understanding these distinctions is crucial for accurately determining the structure and behavior of organic compounds.