See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of Carboxyl Group (-COOH) Presence **Step 1: Identify the structures of each compound** - **(A) Picric acid** ($2,4,6$-trinitrophenol): Contains a phenolic $-OH$ group on benzene ring, not $-COOH$ - **(B) Barbituric acid**: Contains a cyclic structure with $-CO-NH-CO-$ groups, not a free carboxyl group - **(C) Ascorbic acid** (Vitamin C): Contains enediol and lactone functional groups, not a carboxyl group - **(D) Aspirin** (acetylsalicylic acid): Contains both an ester group ($-OCOCH_3$) and a carboxylic acid group ($-COOH$) **Step 2: Verify aspirin's structure** Aspirin has the structure: a benzene ring with $-COOH$ at position 1 and $-OCOCH_3$ at position 2 (ortho position). The free carboxyl group ($-COOH$) is clearly present. **Step 3: Confirm other options lack carboxyl groups** Only aspirin among the four options has an actual carboxylic acid ($-COOH$) functional group. **Answer: (D) Aspirin** — it is the only compound containing the carboxyl functional group.