Question

Name of the compound given below is :

• A. 3-methyl-4-ethyloctane
• B. 2,3-diethylheptane
• C. 5-ethyl-6-methyloctane
• D. 4-ethyl-3-methyloctane

Hint:

Alphabetical order ignores prefixes like di-, tri-, but ethyl comes before methyl.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
IUPAC rules for naming alkanes require:
1. Finding the longest continuous carbon chain.
2. Numbering the chain to give substituents the lowest possible locants.
3. Listing substituents in alphabetical order.
Step 2: Detailed Explanation:
1. Identify the longest chain: If we trace the longest path, we find a chain of 8 carbons, making the parent alkane "octane".
2. Numbering:
- If we start from the top-left branch, the methyl group is at C3 and the ethyl group is at C4. (Locants: 3, 4).
- If we start from the other end, the locants would be higher (5, 6).
- Therefore, we number from the end closer to the methyl branch.
3. Substituents: We have an "ethyl" group at C4 and a "methyl" group at C3.
4. Alphabetical order: "Ethyl" comes before "Methyl".
Name: 4-ethyl-3-methyloctane.
Step 3: Final Answer:
The IUPAC name is 4-ethyl-3-methyloctane.