Rank the following compounds in order of increasing acidity,putting the least acidic first.
A)I

Question

Rank the following compounds in order of increasing acidity,putting the least acidic first. 
A)I < IV < III < II 
B)I < III < IV < II 
C)II < III < IV < I 
D)II < IV < III < I

Quizplus · Accepted Answer

To determine acidity, we look for the stability of the conjugate base. 
I - has no acidic hydrogens 
II - has one acidic hydrogen, but the conjugate base is stabilized by resonance 
III - has one acidic hydrogen, but the conjugate base is not significantly stabilized 
IV - has two acidic hydrogens, but the conjugate base is not significantly stabilized 
Therefore, the order of increasing acidity is I < IV < III < II.

Rank the Following Compounds in Order of Increasing Acidity,putting the Least