Which step in the IUPAC naming process is specific to alkenes but not to alkynes?

• A. Assigning the lowest possible number to the $\mathrm{double} \mathrm{bond}$
• B. Indicating the position of the $\mathrm{unsaturation}$ in the name
• C. Numbering the chain from the end nearest the $\mathrm{functional} \mathrm{group}$
• D. Identifying the longest carbon chain containing the $\mathrm{unsaturation}$

Answer: (A)

Verified step by step guidance

1. Understand that both alkenes and alkynes are unsaturated hydrocarbons, meaning they contain double or triple bonds, respectively.
2. Recall the general IUPAC naming process involves identifying the longest carbon chain that contains the unsaturation (double or triple bond), numbering the chain, and indicating the position of the unsaturation.
3. Note that for both alkenes and alkynes, the chain is numbered to give the lowest possible number to the multiple bond (double or triple bond).
4. Recognize that a key difference is that alkenes specifically require assigning the lowest possible number to the double bond, which is unique because the double bond affects the numbering priority differently than a triple bond in alkynes.
5. Therefore, the step specific to alkenes (and not alkynes) is 'Assigning the lowest possible number to the double bond' during the numbering process.