Distinguishing acid, alcohol, and ester via unique test patterns Steps:

• Warm acidified dichromate oxidizes CH3OH (color change to green), but not CH3COOH or CH3COOCH3.
• Tollens' reagent on CH3OH gives no reaction (neutral, non-reducing).
• Tollens' on CH3COOH causes decomposition due to acidity, forming silver precipitate.
• Tollens' on CH3COOCH3 gives no reaction (neutral, non-reactive).
• Patterns: CH3OH (positive oxidation, negative Tollens'), CH3COOH (negative oxidation, positive Tollens'), CH3COOCH3 (negative both) uniquely identify each.

Why C is correct:

• Tollens' reagent decomposes in acidic conditions (pH drop from CH3COOH protonates NH3, releasing Ag+ to precipitate), distinguishing acid from neutral ester/alcohol.

Why the others are wrong:

• A: 2,4-DNP negative for all; NaHCO3 identifies acid but not alcohol vs. ester (both negative for both).
• B: Tollens' negative for alcohol and ester; warm NaHCO3 identifies acid but not alcohol vs. ester (both negative for both).
• D: 2,4-DNP negative for all; dichromate identifies alcohol but not acid vs. ester (both negative for both).

Final answer: C