When comparing acidity, remember that sulfonic acids are typically stronger acids than carboxylic acids, and carboxylic acids are stronger than phenols.
In this question, we are comparing the acidic strengths of four different compounds.
- M: The compound with the methyl ester group (-COOH) attached to the carboxylic group is the least acidic.
- N: The carboxylic acid group (-COOH) is more acidic than the methyl ester group.
- O: Phenols are weaker acids than carboxylic acids, so this compound will be slightly more acidic.
- P: Sulfonic acids are stronger acids compared to carboxylic acids or phenols, so this compound will be the most acidic.
Thus, M is the least acidic compound.
Final Answer:
M.
