If the substituent name of the OH group is hydroxy in the presence of a carboxylic acid, provide the systematic name for the following compound.

• A. 5-ethyl-4-hydroxyoctanoic acid
• B. 4-ethyl-5-hydroxyoctanoic acid
• C. 5- isopropyl-4-hydroxyoctanoic acid
• D. 4-isopropyl-5-hydroxyoctanoic acid

Answer: (B)

Verified step by step guidance

1. Identify the parent chain: The longest carbon chain containing the carboxylic acid group is octanoic acid (8 carbons with a -COOH group).
2. Number the carbon chain starting from the carboxylic acid carbon as carbon 1, since the carboxylic acid has the highest priority in nomenclature.
3. Locate and identify the substituents on the chain: There is a hydroxy group (-OH) and an alkyl group (ethyl or isopropyl) attached to the chain.
4. Assign the correct position numbers to the substituents based on the numbering from the carboxylic acid end, ensuring the substituents get the lowest possible numbers.
5. Write the systematic name by listing the substituents in alphabetical order with their position numbers, followed by the parent acid name. Remember that when the -OH is a substituent (not the principal functional group), it is named as 'hydroxy'.