What is the IUPAC name of this alkane?
4-ethyl-2,2-dimethylpentane
2-ethyl-4,4-dimethylpentane
2-ethyl-2,2-dimethylpentane
2,2,4-trimethylhexane
The Correct Answer and Explanation is :
The IUPAC name of the alkane in question is 2,2,4-trimethylhexane.
Explanation:
The compound consists of a six-carbon chain (hexane) with three methyl groups attached:
- Two methyl groups are attached to the second carbon atom (2,2-).
- One methyl group is attached to the fourth carbon atom (4-).
This configuration results in the IUPAC name 2,2,4-trimethylhexane.
Structural Analysis:
- Parent Chain: The longest continuous chain contains six carbon atoms, corresponding to “hexane.”
- Substituents:
- Two methyl groups (-CH₃) are attached to the second carbon atom.
- One methyl group is attached to the fourth carbon atom.
This structure is consistent with the IUPAC naming conventions for alkanes with multiple substituents.
Alternative Names:
The other names provided are common names or less systematic names:
- 4-ethyl-2,2-dimethylpentane: Suggests a five-carbon chain (pentane) with an ethyl group on the fourth carbon and two methyl groups on the second carbon.
- 2-ethyl-4,4-dimethylpentane: Indicates a five-carbon chain with an ethyl group on the second carbon and two methyl groups on the fourth carbon.
- 2-ethyl-2,2-dimethylpentane: Implies a five-carbon chain with an ethyl group and two methyl groups on the second carbon.
These names do not accurately describe the structure of the compound, as they suggest different carbon chain lengths and substituent positions.
Conclusion:
The correct IUPAC name for the compound is 2,2,4-trimethylhexane, accurately reflecting its structure as a six-carbon chain with two methyl groups on the second carbon and one on the fourth carbon.