Question

Which of the following is most acidic?

• A. CF3COOH
• B. CCl3COOH
• C. CHCl2COOH
• D. CH3COOH

Hint:

Electronegative substituents, like CF\(_3\), increase the acidity of carboxylic acids by stabilizing the negative charge on the conjugate base.

Answer 1

The Correct Option is A

Step 1: Understanding the effect of substituents.
The acidity of carboxylic acids increases with the electronegativity of the substituent attached to the aromatic ring or the alpha-carbon. The electron-withdrawing effect of fluorine (in CF\(_3\)) is stronger than that of chlorine (in CCl\(_3\) or CHCl\(_2\)) or hydrogen (in CH\(_3\)).

Step 2: Identifying the most acidic compound.
Among the given acids, CF\(_3\)COOH has the strongest electron-withdrawing group (CF\(_3\)), which increases its acidity.

Step 3: Conclusion.
The most acidic compound is CF\(_3\)COOH, which corresponds to option (1).