Question

IUPAC name of the compound given below is:

• A. 4-Ethyl-3-methyloctane
• B. 3-Methyl-4-ethyloctane
• C. 2,3-Diethylheptane
• D. 5-Ethyl-6-methylocatane

Answer 1

The Correct Option is A

To determine the IUPAC name of the given compound, we need to follow the standard IUPAC nomenclature rules for alkanes:

1. Identify the longest continuous carbon chain. This will determine the base name of the compound.
2. Identify all substituents (side chains) attached to the longest chain.
3. Number the carbon atoms in the longest chain, starting from the end nearest a substituent.
4. Write the name as a single word, using hyphens to separate numbers from letters and commas to separate numbers.

Let's apply these rules to the given compound:

1. The longest continuous carbon chain contains 8 carbon atoms, hence the base name is "octane".
2. There are two substituents: an ethyl group (–CH₂CH₃) and a methyl group (–CH₃).
3. Numbering the chain from left to right (considering the nearest substituent), we get:
   • Ethyl group at position 4.
   • Methyl group at position 3.
4. Thus, the IUPAC name is: 4-Ethyl-3-methyloctane.

Let's look at why the other options are incorrect:

• 3-Methyl-4-ethyloctane: While this option uses correct substituents, the order of substituents should follow alphabetical precedence regardless of their numbers.
• 2,3-Diethylheptane: This doesn't match the structure, as the main chain is not 7 carbons long and does not have two ethyl groups.
• 5-Ethyl-6-methyloctane: Incorrect numbering; it doesn't provide the lowest numbers for the substituents.

Hence, the correct answer is 4-Ethyl-3-methyloctane.