Question

IUPAC name of the following compound (P) is:

• A. 1-Ethyl-5, 5-dimethylcyclohexane
• B. 3-Ethyl-1,1-dimethylcyclohexane
• C. 1-Ethyl-3, 3-dimethylcyclohexane
• D. 1,1-Dimethyl-3-ethylcyclohexane

Answer 1

The Correct Option is B

The image displays a cyclohexane derivative substituted with alkyl groups. The IUPAC name is determined as follows:

1. Main chain identification: The core structure is a cyclohexane ring.
2. Substituent identification:
   • An ethyl group is present.
   • Two methyl groups are attached to a single carbon atom.
3. Carbon atom numbering: The ring is numbered to assign the lowest locant set to the substituents.
   • Numbering commences from the carbon bearing the two methyl groups, designated as position 1.
   • Clockwise numbering places the ethyl group at position 3.
4. Name compilation:
   • The compound is named 3-Ethyl-1,1-dimethylcyclohexane, reflecting substituent types and positions.

Consequently, the IUPAC name is established as 3-Ethyl-1,1-dimethylcyclohexane.

Evaluation of provided options:

• 1-Ethyl-5,5-dimethylcyclohexane - Incorrect locant assignment for substituents.
• 3-Ethyl-1,1-dimethylcyclohexane - Correct, consistent with the derived name.
• 1-Ethyl-3,3-dimethylcyclohexane - Incorrect ethyl group position.
• 1,1-Dimethyl-3-ethylcyclohexane - Incorrect alphabetical order of substituents.