Question

Arrange the following compounds A, B, C, and D in decreasing order of acidic strength:


Choose the correct answer from the options given below:

• A. B > D >C >A
• B. A > C >D>B
• C. A > D >C >B
• D. B > C >A>D

Hint:

Electron-withdrawing groups like NO2 and SO3H increase acidity, while electrondonating groups such as OCH3 and CH3 reduce acidity.

Answer 1

The Correct Option is B

The acidity of these compounds is dictated by the substituents on the aromatic ring, which affect electron density.

• Compound A: Contains two electron-withdrawing \( NO_2 \) groups, enhancing acidity.
• Compound B: Features a strong electron-withdrawing \( SO_3H \) group, increasing acidity, but less so than the two \( NO_2 \) groups in A.
• Compound C: Includes an electron-donating \( OCH_3 \) group, reducing acidity.
• Compound D: Possesses an electron-donating \( CH_3 \) group, further decreasing acidity.

Therefore, the acidity order is \( A > C > D > B \), with A being the most acidic, followed by C, D, and B.