Final answer:
To determine the molecule with the longest C-C bond, identify the longest continuous chain containing the bond and number the chain from the end nearest a functional group or multiple bond. Molecules with double or triple bonds in the chain will have names ending respectively, with numbering prioritized to give these bonds the lowest possible numbers.
Step-by-step explanation:
To see which compound contains the longest carbon-carbon (C-C bond), you can follow a systematic approach:
- Find the longest continuous chain of carbon atoms in the molecule. This chain, known as the parent chain, should include the bond of interest (double or triple bond if present).
- When you encounter functional groups such as a C-C triple bond, this must be included in the parent chain, and the molecule will be named accordingly (e.g., as an alkyne for a triple bond).
- Number the carbon atoms in the parent chain starting from the end closest to the functional group or multiple bond to assign the smallest possible numbers to these features.
- If there are substituents like methyl groups, number the chain in such a way as to give these substituents the lowest possible numbers.
- For example, a molecule with six carbon atoms that contains a triple bond starting from the third carbon atom will be named as a hexyne (3-hexyne in this case). If there are additional substituents, such as methyl groups in the 2,2 positions, the molecule is named 2,2-dimethyl-3-hexyne, because the triple bond takes precedence in numbering over the methyl groups.
Additionally, the hybridization and bond angles may indicate the length of the bond. In alkenes and alkynes, the carbon atoms involved in double and triple bonds have sp2 and sp hybridization, respectively, resulting in shorter bond lengths compared to single bonds (alkane's sp3 hybridization).