Question

What is IUPAC name of following compound?

Choose the correct answer from the options given below.

• A. 3-Carboxy-4-methyl benzaldehyde
• B. 5-Carboxy-4-methyl benzaldehyde
• C. 3-Formyl-6-methyl benzoic acid
• D. 5-Formyl-6-methyl benzoic acid

Hint:

Isolate the principal group first to find the parent name. Since $-\mathrm{COOH}$ takes absolute priority, the compound must end with "benzoic acid". This immediately eliminates options (A) and (B), leaving a simple choice based on counting positions.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
A trisubstituted benzene bears -CH₃, -COOH, and -CHO groups. We must assign the correct IUPAC name following priority rules.

Step 2: Key Formula or Approach:
IUPAC seniority order: -COOH>-CHO>-R. The principal group determines the parent name (benzoic acid) and defines position 1. Other substituents become prefixes listed alphabetically.

Step 3: Detailed Explanation:
-COOH takes priority, so the parent is benzoic acid at position 1. Numbering toward the nearest substituent places -CHO at position 3 and -CH₃ at position 6. Alphabetically, "Formyl" precedes "Methyl". Thus the name is 3-Formyl-6-methyl benzoic acid.

Step 4: Final Answer:
The correct IUPAC name is 3-Formyl-6-methyl benzoic acid, option (C).