Rank the following compounds in order of decreasing acidity,starting with the most acidic.
A)I II III
B)III II I
C)III I II
D)I III II

Question

Rank the following compounds in order of decreasing acidity,starting with the most acidic. 
A)I > II > III 
B)III > II > I 
C)III > I > II 
D)I > III > II

Quizplus · Accepted Answer

The acidity of a compound is determined by the stability of its conjugate base. The more stable the conjugate base, the stronger the acid. In this case, compound III has a resonance-stabilized conjugate base, making it the strongest acid. Compound II also has a resonance structure in its conjugate base, but it is not as stable as the one for III. Compound I does not have any resonance stabilization in its conjugate base, making it the weakest acid. Therefore, the correct order of decreasing acidity is III > II > I, which is represented by choice B.

Rank the Following Compounds in Order of Decreasing Acidity,starting with the Most