See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Step 1 - Establish the concepts: - H-bond DONOR: a molecule that has a hydrogen atom directly bonded to a highly electronegative atom (N, O, or F), i.e., N-H, O-H, or F-H bonds. - H-bond ACCEPTOR: a molecule that has a lone pair on a highly electronegative atom (N, O, F) that can accept a hydrogen bond from another molecule. - A molecule can be ONLY a donor if it has N-H/O-H/F-H but its electronegative atom(s) cannot accept (unusual, but HF is borderline; however in this classification scheme the answer key places HF under donors-only category B, meaning it is both donor and acceptor). - Actually re-reading the answer: A (only donors) = a, c, f, g, k, l; B (both donor and acceptor) = b, d, h, j; C (no H-bonding) = e, i. Step 2 - Analyze each compound: (a) Bicyclic tertiary amine (pyrrolizidine-type): The nitrogen is tertiary (no N-H bond), so it CANNOT donate H-bonds. It has a lone pair on N, so it CAN accept H-bonds. Therefore it is an acceptor only. The answer key places it in A (only donor). Wait - re-examining: the answer says A includes a. Let me reconsider the question wording. Question A asks 'only as H-bond donors' but perhaps the intended meaning in this question bank is 'only as H-bond acceptors' for A, or the labeling of A/B/C differs. Actually, looking again at the answer: A={a,c,f,g,k,l} and B={b,d,h,j}. Let me re-read the questions: A=only donors, B=both donor and acceptor, C=no H-bonding. This seems inconsistent with standard chemistry for (a). However, given the answer key is ground truth, the intended interpretation must be: A = compounds that can serve ONLY as H-bond ACCEPTORS (not donors), B = compounds that serve as BOTH donors AND acceptors, C = no H-bonding participation. Step 3 - Re-interpret with corrected reading (A = only acceptors, based on structures matching the answer): (a) Tertiary bicyclic amine - lone pair on N, no N-H: ONLY acceptor → A ✓ (c) Ethyl acetate (ester) - lone pairs on O, no O-H: ONLY acceptor → A ✓ (f) Tetrahydrofuran - lone pairs on O, no O-H: ONLY acceptor → A ✓ (g) Cyclohexanone - lone pairs on C=O oxygen, no O-H: ONLY acceptor → A ✓ (k) N-acetylpyrrolidine (tertiary amide) - lone pairs on O and N, no N-H or O-H: ONLY acceptor → A ✓ (l) Diphenyl ether - lone pairs on O, no O-H: ONLY acceptor → A ✓ (b) Isobutanol - has O-H (donor) AND lone pairs on O (acceptor): BOTH → B ✓ (d) HF - has F-H (donor) AND lone pairs on F (acceptor): BOTH → B ✓ (h) Cyclopentanecarboxylic acid - has O-H (donor) AND lone pairs on both oxygens (acceptor): BOTH → B ✓ (j) Aniline - has N-H bonds (donor) AND lone pair on N (acceptor): BOTH → B ✓ (e) Tert-butylcyclopentane - all C-H and C-C bonds, no heteroatoms: NO H-bonding → C ✓ (i) Bicyclo[4.2.0]octane (cyclohexane fused cyclobutane) - all C-H and C-C bonds, no heteroatoms: NO H-bonding → C ✓ Step 4 - Why the question text says 'donors' for A but the answer corresponds to 'acceptors': The question as printed likely has A asking 'only as H-bond acceptors' (a transcription/OCR issue in the problem statement image, or the question bank uses a different ordering). The ground-truth answer is consistent with A = only acceptors, B = both, C = neither. Therefore, the correct answer is {"A": ["a", "c", "f", "g", "k", "l"], "B": ["b", "d", "h", "j"], "C": ["e", "i"]}.