Question

IUPAC name of following hydrocarbon (X) is :

• A. 2-Ethyl-3,6-dimethylheptane
• B. 2-Ethyl-2,6-diethylheptane
• C. 2,5,6-Trimethyloctane
• D. 3,4,7-Trimethyloctane

Answer 1

The Correct Option is C

To determine the IUPAC name of the given hydrocarbon, follow these steps:

1. Identify the longest carbon chain in the structure. In this case, the longest chain consists of 8 carbon atoms. Therefore, the base name of the compound is "octane".
2. Number the carbon chain in such a way that gives the substituents (methyl groups in this case) the lowest possible numbers.
3. Identify and name the substituents:
   • At carbon 2, there is a methyl group.
   • At carbon 5, there is another methyl group.
   • At carbon 6, there is a third methyl group.
4. Combine the names of the substituents with the base name, numbering them accordingly:
   • There are three methyl groups, so the prefixes are combined as "trimethyl".
   • The list of substituents by position will be 2,5,6.
5. The complete IUPAC name of the compound is "2,5,6-Trimethyloctane".

This matches the correct answer option provided.

Answer 2

To determine the IUPAC name of the given hydrocarbon, follow these steps:

1. Identify the longest continuous carbon chain. In the given hydrocarbon, the longest chain contains 8 carbon atoms. Hence, the parent hydrocarbon is an octane.
2. Number the carbon atoms in the longest chain starting from the end nearest to a branch. This helps in assigning the lowest possible numbers to the substituents. For this molecule, starting from the left end provides substituents at position 2, 5, and 6.
3. Identify and name the substituents attached to the main chain. There are three methyl groups at positions 2, 5, and 6.
4. Combine the names of the substituents with the parent chain. Use prefixes to indicate the number of identical substituents (e.g., "tri-" for three).
5. Thus, the IUPAC name of the hydrocarbon is 2,5,6-Trimethyloctane.

Therefore, the correct answer is 2,5,6-Trimethyloctane.