Give a systematic name for the below compound.

• A. 1-sec-butyl-3-methylcyclopentane
• B. 1-methyl-3-sec-butylcyclopentane
• C. 1-butyl-3-methylcyclopentane
• D. 1-methyl-3-butylpentane

Answer: (A)

Verified step by step guidance

1. Identify the main carbon chain in the compound. In this case, the main ring is a cyclopentane, which is a five-membered carbon ring.
2. Determine the substituents attached to the cyclopentane ring. Here, there are two substituents: a methyl group (CH3) and a sec-butyl group.
3. Number the carbon atoms in the cyclopentane ring to give the substituents the lowest possible numbers. Start numbering from the carbon with the sec-butyl group, as it is the larger substituent, and proceed in the direction that gives the next substituent the lowest number.
4. Assign the numbers to the substituents based on the numbering of the ring. The sec-butyl group is on carbon 1, and the methyl group is on carbon 3.
5. Combine the information to write the systematic name. The name is constructed by listing the substituents in alphabetical order followed by the name of the main chain. Therefore, the systematic name is 1-sec-butyl-3-methylcyclopentane.