Provide the IUPAC names for the following alkynes.
(b)

Verified step by step guidance

1. Step 1: Identify the longest continuous carbon chain that contains the triple bond. This chain will serve as the parent chain for naming the alkyne.
2. Step 2: Number the parent chain starting from the end closest to the triple bond. This ensures the triple bond gets the lowest possible number.
3. Step 3: Determine the position of the triple bond within the chain and include this number in the name. Use the suffix '-yne' to indicate the presence of a triple bond.
4. Step 4: Identify and name any substituents attached to the parent chain. Use prefixes such as 'methyl-', 'ethyl-', etc., and specify their positions based on the numbering of the parent chain.
5. Step 5: Combine the substituent names, parent chain name, and triple bond position into the full IUPAC name, ensuring proper order and formatting (substituents listed alphabetically, followed by the parent chain with the triple bond position).

Key Concepts

Alkynes

Alkynes are a class of hydrocarbons characterized by at least one carbon-carbon triple bond. They follow the general formula CnH2n-2, where 'n' is the number of carbon atoms. Alkynes are unsaturated compounds, which means they contain fewer hydrogen atoms than alkanes and alkenes. The presence of the triple bond gives alkynes unique reactivity and properties compared to other hydrocarbons.

IUPAC Nomenclature

The International Union of Pure and Applied Chemistry (IUPAC) nomenclature is a systematic method for naming chemical compounds. For alkynes, the naming convention involves identifying the longest carbon chain containing the triple bond, numbering the chain to give the lowest possible number to the triple bond, and using the suffix '-yne' to indicate the presence of the triple bond. This standardized approach ensures clear communication among chemists regarding the structure of compounds.

Numbering and Locants

In IUPAC nomenclature, numbering the carbon chain is crucial for indicating the position of functional groups, such as triple bonds in alkynes. The locant is the number assigned to the carbon atom where the triple bond begins, ensuring that the name reflects the compound's structure accurately. For example, in 2-butyne, the '2' indicates that the triple bond starts at the second carbon of the four-carbon chain, which is essential for distinguishing between isomers.