Rank the labeled protons (H_a-H_d)in order of increasing acidity,starting with the least acidic.

Question

Quizplus · Accepted Answer

The acidity of a proton is determined by the stability of the resulting anion after it loses a proton. The more stable the anion, the more acidic the proton. In this case, the stability of the anion can be determined by the presence of nearby electron-withdrawing groups. Hb is adjacent to a carbonyl group, making the resulting anion stabilized by resonance. Hc is next to a positively-charged nitrogen, which also has a stabilizing effect. Ha is next to a sulfur, which can stabilize the anion by inductive effects, but not as effectively as the other two. Finally, Hd is adjacent to a carbon, which does not have any stabilizing or destabilizing effects. Therefore, the order of increasing acidity is Hb < Hc < Ha < Hd, making choice B the correct answer.

Rank the Labeled Protons (Ha-Hd)in Order of Increasing Acidity,starting with the Least

Rank the Labeled Protons (H_a-H_d)in Order of Increasing Acidity,starting with the Least