Rank the following compounds in order of decreasing acidity,putting the most acidic first.

Question

Quizplus · Accepted Answer

The acidity of an organic compound is determined by the stability of the conjugate base that is formed when the compound loses a proton. The more stable the conjugate base, the more acidic the compound.
IV (carboxylic acid) is the most acidic compound because the carbonyl group withdraws electron density from the O-H bond, making it easier to lose a proton. The resulting carboxylate ion is stabilized by resonance delocalization. 
III (phenol) is less acidic because the phenoxide ion is not as stabilized by resonance delocalization as the carboxylate ion. 
II (alcohol) is even less acidic because the alkoxide ion is even less stabilized by resonance delocalization than the phenoxide ion. 
I (alkane) is the least acidic because it lacks any acidic protons.

Rank the Following Compounds in Order of Decreasing Acidity,putting the Most