Question

The correct order of acid strength of the following carboxylic acids is:

• A. I>II>III>IV
• B. III>II>I>IV
• C. II>I>IV>III
• D. I>III>II>IV

Answer 1

The correct option is A

I>II>III>IV

The correct option is (A):

Explanation for the correct answer:

Acid-strength:-

1. It is basically defined as the tendency or the ability to lose a proton.
2. Actually the strength of the acid in the organic compound is just directly proportional to the acid's conjugate base's stability.
3. So the carboxylate ion that is formed is actually the conjugate base of the carboxylic acid and so further is stabilized by the resonating structures so that the negative charge can be delocalized easily.
4. For increasing the stability of the carboxylate ion that is basically a conjugate base, there is a requirement of the electron-withdrawing groups, so that the negative charge can be easily delocalized in the two electronegative Oxygen atoms in the two resonating structures.
5. Hence, $$\begin{gathered} \mathrm{Acidity}\mathrm{of}\mathrm{carboxylic}\mathrm{acid}\mathrm{\alpha }-\mathrm{R}>-\mathrm{H}>-\mathrm{I} \\ \mathrm{Acidic}\mathrm{strength}\mathrm{\alpha }\mathrm{Stability}\mathrm{of}\mathrm{conjugate}\mathrm{anion} \end{gathered}$$

Therefore, the correct option is (A) :- I>II>III>IV.