Which is the most acidic proton in the following compound: ${\mathrm{CH}}_3\mathrm{COOH}$?

• A. The hydrogen atom of the carboxyl group ($\mathrm{COOH}$)
• B. One of the hydrogens of the methyl group (${\mathrm{CH}}_3$)
• C. There is no acidic proton in this compound
• D.

Answer: (A)

Verified step by step guidance

1. Identify all the types of hydrogen atoms present in the compound CH\_3COOH. Here, there are hydrogens attached to the methyl group (CH\_3) and one hydrogen attached to the carboxyl group (COOH).
2. Recall the concept of acidity in organic molecules: acidity depends on the stability of the conjugate base formed after the proton is lost. The more stable the conjugate base, the more acidic the proton.
3. Analyze the acidity of the methyl hydrogens (CH\_3). These hydrogens are attached to a carbon atom, which generally does not stabilize the negative charge well after deprotonation, making them weakly acidic or essentially non-acidic.
4. Analyze the acidity of the carboxyl hydrogen (COOH). When this proton is lost, the resulting carboxylate ion is resonance stabilized, distributing the negative charge over two oxygen atoms, which greatly increases acidity.
5. Conclude that the most acidic proton in CH\_3COOH is the hydrogen of the carboxyl group (COOH) due to resonance stabilization of its conjugate base.