To determine the IUPAC name for the compound [tex]\( CH_3-CH_2-C \equiv C-CH_3 \)[/tex], follow these systematic steps:
1. Identify the Longest Carbon Chain Containing the Triple Bond:
- In this case, we have a chain of 5 carbon atoms in a straight line, making it a derivative of pentane with a triple bond (alkyne). The five carbon atoms are:
[tex]\[
CH_3-CH_2-C \equiv C-CH_3
\][/tex]
The backbone is a pentane chain with the triple bond indicating that it is an alkyne.
2. Number the Carbon Chain:
- Number the carbon atoms in the chain starting from the end that gives the triple bond the lowest possible number. Hence, we begin numbering the carbon atoms from the end closer to the triple bond:
[tex]\[
1-CH_3 , 2-CH_2 , 3-C , 4\equiv C , 5-CH_3
\][/tex]
- Numbering from left to right, the triple bond starts at carbon 2 (between carbon atoms 2 and 3).
3. Assign the Position Number to the Triple Bond:
- Since the triple bond starts at carbon 2, this compound is specifically an alkyne substituted at the second carbon position. Therefore, it is named as a 2-pentyne.
4. Construct the IUPAC Name:
- Combine the root name (pentane) with the suffix for a triple bond (yne) and indicate the position of the triple bond. Hence, the IUPAC name for [tex]\( CH_3-CH_2-C \equiv C-CH_3 \)[/tex] is 2-pentyne.
After following these steps, we can conclude that the IUPAC name for [tex]\( CH_3-CH_2-C \equiv C-CH_3 \)[/tex] is 2-pentyne.
