Question

Please help...and explain..

Rank the acidity of the protons shown in the picture (from most acidic to least) I > II > III = IV IV > I = II > III IV > I > II > II I > II > IV > III What accounts for the difference between the acidity of proton (IV) and protons (I and II)? (may be more than one answer) Feature 1: energy and entropy stabilization Feature 2: energy and entropy stabilization (delocalization- resonance) Feature 3: bond polarization energy stabilization all three none of the above Please rank the acidity of each of the protons designated in the picture. (from most acidic to least) I > III > II II > I > III I > II > III III > II > I What best describes the difference between the acidity of proton at position III vs II? Feature 1: energy and entropy stabilization Feature 2: energy and entropy stabilization: (effect of resonance) Feature 3: Bond polarization energy stabilization HO D they are the same cannot tell with this information

Answer 1

Protons (I) , (II), (IV) are the Carboxylic group therefore the directly attached by Central carbon atom and placed between two carbonyl group Hence (IV) is more electronegative therefore (IV) proton is more acidic. (I) and (II) has same electro negativity therefore it has equal acidity. (III) proton represent the alcohol group hence it is less electronegative in the comparison of all proton. Hence Answer is (B) IV > I = II > III (D) all three because the difference between the acidity of proton (IV) and proton (I & II) is resonance. The resonance is occurred when bond polarization energy and entropy stabilization. Here the (I) proton is more acidic because its attached with more electronegative (C l) atom. Proton (II) is less acidic to proton (I) and more acidic to proton (III) because it is near to central carbon atom due to this the resonance is occurred causes