Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

Question

Quizplus · Accepted Answer

The acidity of a hydrogen is determined by the stability of its conjugate base. The more stable the conjugate base, the more acidic the hydrogen. In compound V, the resulting anion after removing the hydrogen is directly stabilized by the electronegative oxygen atom. In compounds III and I, the anions are stabilized by resonance with neighboring electronegative atoms. In compound II, the anion is stabilized by delocalization through the pi bond. In compound IV, there is no significant stabilization of the resulting anion. Therefore, the order of increasing acidity is IV < II < I, III < V. Thus, the correct ranking is E) V > III > I > II > IV.

Rank the Bold-Faced Hydrogens for the Following Compounds from Most