See image — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

Step 1 — Classify each substrate: A: Chlorocyclohexene — allylic/secondary chloride on a cyclohexene ring. Reactive toward SN2 and E2; allylic position activates substitution. B: Benzyl chloride (PhCH2Cl) — primary benzylic; very reactive SN2, also SN1 possible. C: CH3I — methyl iodide; primary, best SN2 substrate, no elimination possible (no beta-H on carbon with H only). D: Vinylic chloride (H3C)2C=CHCl — vinylic halide; extremely unreactive toward both SN2 and E2. No reaction. E: Aryl chloride (chlorobenzene derivative) — aryl halide; no SN2 (sp2 carbon), no E2. No reaction under normal nucleophilic conditions. F: Tertiary bromide on cyclohexane with gem-dimethyl substituents (very hindered tertiary) — too hindered for SN2; E2 possible with strong base, but with weak nucleophiles/bases no reaction or very slow. G: 3-Chloro-3-ethylpentane — tertiary chloride, hindered. SN2 blocked; E2 with strong base, but with weak nucleophiles slow/no reaction, with strong base elimination. H: Trans-fused bicyclic bromide (trans-2-bromodecalin type) — trans diaxial arrangement needed for E2; trans-decalin system. For E2, requires anti-periplanar H — in trans-decalin the bromide is trans to available H, E2 is possible. For SN2, secondary but hindered in rigid bicyclic. With good nucleophiles substitution occurs; with strong base elimination. I: Primary alkyl bromide (CH2Br on cyclopentane ring) — primary bromide, good SN2 substrate. Substitution with all nucleophiles. With strong base (NaOH) could also eliminate but primary substrates favor substitution. J: Tertiary bromide on cyclopentane (Br and CH3 on same carbon, tertiary) — hindered, SN2 blocked. E2 with strong base; with weak nucleophiles no reaction or slow. Step 2 — Nucleophile properties: (i) CH3CO2Na (acetate): weak nucleophile, weak base. Favors SN2 for reactive substrates; cannot promote E2 efficiently. (ii) CH3SNa (methylthiolate): good nucleophile (soft, polarizable sulfur), weak base. Strong SN2 nucleophile, poor at E2. (iii) NaCN (cyanide): good nucleophile, moderate base. Good SN2. (iv) NaOH (hydroxide): good nucleophile AND strong base. Can do both SN2 and E2. Step 3 — Apply to each compound: Compound A (allylic secondary chloride): - All nucleophiles: substitution (SN2 at allylic position) → (2) for i, ii, iii - NaOH: substitution and elimination possible → (4) Compound B (benzyl chloride, primary): - All nucleophiles: SN2 substitution → (2) for i, ii, iii - NaOH: primary, substitution favored, but some elimination possible; however benzyl primary strongly favors substitution → (2) Compound C (CH3I, methyl): - All nucleophiles: SN2 only (no β-H for elimination) → (2) for all Compound D (vinylic chloride): - All nucleophiles: no reaction → (1) for all Compound E (aryl chloride): - All nucleophiles: no reaction under these conditions → (1) for all Compound F (very hindered tertiary bromide): - Acetate (weak nuc, weak base): no reaction → (1) - Methylthiolate (good nuc, weak base): good nucleophile but very hindered tertiary — slow/no substitution → (5) - Cyanide (good nuc, moderate base): also hindered, no reaction → (1) - NaOH (strong base): E2 possible but hindered neopentyl-type — slow/no reaction or slow elimination → (5) Compound G (tertiary chloride, 3-ethyl-3-chloropentane): - Acetate (weak base/nuc): no SN2 at tertiary; no E2 with weak base → slow/no elimination (6) - Methylthiolate (good nuc, weak base): SN2 blocked at tertiary; weak base so no E2 → slow/no elimination (6) - Cyanide (good nuc, moderate base): tertiary, SN2 blocked; but cyanide is better base than acetate → E2 possible → (3) - NaOH (strong base): E2 → (3) Compound H (trans-bicyclic secondary bromide): - Anti-periplanar geometry in trans-decalin allows E2. For SN2, it is secondary in a rigid ring — accessible. - Acetate (weak nuc, weak base): substitution at secondary → (2) - Methylthiolate (good nuc, weak base): substitution → (2) - Cyanide (good nuc, moderate base): in rigid bicyclic system, E2 is geometrically favorable (anti-periplanar H available in trans system) → (3) - NaOH (strong base): E2 → (3) Compound I (primary CH2Br on cyclopentane): - All nucleophiles: SN2 → (2) for i, ii, iii - NaOH: primary → substitution + some elimination → (4) Compound J (tertiary bromide on cyclopentane, hindered): - Acetate (weak base): no SN2 at tertiary; weak base → no E2 → slow elimination (6) - Methylthiolate (weak base): SN2 blocked; weak base → slow elimination (6) - Cyanide (moderate base): E2 possible → (3) - NaOH (strong base): E2 → (3) Step 4 — Compile the grid: (i) Acetate: A=2, B=2, C=2, D=1, E=1, F=1, G=6, H=2, I=2, J=6 (ii) Methylthiolate: A=2, B=2, C=2, D=1, E=1, F=5, G=6, H=2, I=2, J=6 (iii) Cyanide: A=2, B=2, C=2, D=1, E=1, F=1, G=3, H=3, I=2, J=3 (iv) Hydroxide: A=4, B=2, C=2, D=1, E=1, F=5, G=3, H=3, I=4, J=3 Key reasoning notes: - D and E are vinylic/aryl halides → no reaction (1) with all nucleophiles. - C is methyl → only substitution (2), no elimination possible. - F is very hindered tertiary (neopentyl-like on ring) → SN2 impossible; E2 only with very strong base; acetate/cyanide give no reaction (1), methylthiolate/hydroxide give slow/no reaction or slow substitution/elimination (5). - G tertiary: acetate and methylthiolate (weak bases) → slow elimination (6); cyanide and hydroxide (stronger bases) → elimination (3). - H trans-bicyclic secondary: acetate and methylthiolate → substitution (2); cyanide and hydroxide → elimination (3) due to rigid anti-periplanar geometry favoring E2. - J tertiary cyclopentane: acetate and methylthiolate → slow elimination (6); cyanide and hydroxide → elimination (3). - A allylic secondary: acetate/methylthiolate/cyanide → substitution (2); hydroxide (strong base+nuc) → substitution and elimination (4). - I primary: acetate/methylthiolate/cyanide → substitution (2); hydroxide → substitution and elimination (4). - B benzyl primary: substitution (2) with all (hydroxide gives substitution as primary benzylic strongly favors SN2). Therefore, the correct answer is {"i": {"A": "2", "B": "2", "C": "2", "D": "1", "E": "1", "F": "1", "G": "6", "H": "2", "I": "2", "J": "6"}, "ii": {"A": "2", "B": "2", "C": "2", "D": "1", "E": "1", "F": "5", "G": "6", "H": "2", "I": "2", "J": "6"}, "iii": {"A": "2", "B": "2", "C": "2", "D": "1", "E": "1", "F": "1", "G": "3", "H": "3", "I": "2", "J": "3"}, "iv": {"A": "4", "B": "2", "C": "2", "D": "1", "E": "1", "F": "5", "G": "3", "H": "3", "I": "4", "J": "3"}}.