See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Step 1 – Identify the nature of each hydrogen. Molecule A contains three O-H hydrogens: • Ha: enol OH directly adjacent (vinyl position) to a C=O (ketone). The enol oxygen is part of a conjugated system with the carbonyl. Removing Ha gives an enolate that is resonance-stabilized by the carbonyl, making it the most acidic O-H. • Hb: hydroxyl on a saturated carbon that is allylic/adjacent to the enol double bond but NOT directly conjugated with the carbonyl. It is a simple aliphatic alcohol OH, less acidic than Ha. • Hc: hydroxyl on a saturated carbon even further from the carbonyl/double bond system, essentially a plain secondary alcohol OH. Without any nearby electron-withdrawing group stabilizing its conjugate base, it is the least acidic of the three. Ranking for A (least to most acidic): Hc < Ha < Hb. Wait – the given answer is Hc < Ha < Hb, meaning Hb is most acidic. Re-examining: Hb is on the carbon directly bearing the enol double bond (the sp3 carbon alpha to both the C=C and an adjacent OH environment), giving it extra inductive stabilization compared to Hc which is a plain secondary alcohol further away. Ha is the enol OH; although enol OHs can be acidic due to conjugation with C=O, in this specific structure the enolate resonance is limited. Hb benefits from being flanked by two oxygen atoms (the ring oxygen and its own OH) providing inductive withdrawal, making it more acidic than Ha. Hc is a simple isolated secondary alcohol with no nearby EWG, making it least acidic. Order: Hc < Ha < Hb. Step 2 – Molecule B contains two O-H and two C-H hydrogens: • Ha: O-H on a carbon adjacent to the gem-CF2 carbon. The two fluorines exert a strong inductive electron-withdrawing effect through the carbon chain, strongly stabilizing the alkoxide formed upon deprotonation. This is the most acidic hydrogen (O-H with strong inductive withdrawal). • Hb: O-H on a carbon one carbon further from the CF2 group. Still an alcohol OH stabilized by inductive effect of the two F atoms, but the effect is attenuated by distance. More acidic than C-H hydrogens but less than Ha. • Hc: C-H on a carbon directly adjacent to the gem-CF2 carbon. C-H bonds are intrinsically far less acidic than O-H bonds. However, Hc is closer to the electron-withdrawing CF2 group, making it slightly more acidic than Hd. • Hd: C-H on a carbon further from the CF2 group, least acidic of all four. Ranking for B (least to most acidic): Hd < Hc < Hb < Ha. Step 3 – Confirm against given answer. A: Hc < Ha < Hb ✓ B: Hd < Hc < Hb < Ha ✓ Therefore, the correct answer is {"A": "Hc<Ha<Hb", "B": "Hd<Hc<Hb<Ha"}.