See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

To classify each substituent for electrophilic aromatic substitution (EAS), we apply two key concepts: 1. ACTIVATING vs DEACTIVATING: Electron-donating groups (EDG) activate the ring; electron-withdrawing groups (EWG) deactivate it. 2. ORTHO/PARA vs META DIRECTING: EDGs (except halogens) direct ortho/para. Halogens are deactivating but ortho/para directing due to lone pair donation despite inductive withdrawal. Most EWGs direct meta. However, some deactivating groups that can stabilize the ortho/para carbocation intermediate through resonance still direct ortho/para. Analysis of each substituent: 1. -OCH3 (methoxy): Strong EDG via lone pair donation. Activating, ortho/para directing. (Activating: true, Deactivating: false, O/P: true, Meta: false) 2. -C(=O)OCH3 (ester, carbonyl attached to ring): EWG via resonance withdrawal through carbonyl. Deactivating, meta directing. (Activating: false, Deactivating: true, O/P: false, Meta: true) 3. -OC(=O)CH3 (acetate ester, oxygen attached to ring): The oxygen attached directly to ring donates lone pairs, making it activating and ortho/para directing (similar to -OR groups), despite the carbonyl farther away. Net effect: activating, ortho/para. (Activating: true, Deactivating: false, O/P: true, Meta: false) 4. -CH3 (methyl): Weak EDG via hyperconjugation/induction. Activating, ortho/para directing. (Activating: true, Deactivating: false, O/P: true, Meta: false) 5. -F (fluoro): Deactivating by induction (very electronegative) but ortho/para directing by lone pair resonance donation. (Activating: false, Deactivating: true, O/P: true, Meta: false) 6. -Ph (phenyl): Weak activating EDG via resonance conjugation; ortho/para directing. (Activating: true, Deactivating: false, O/P: true, Meta: false) 7. -NHC(=O)CH3 (acetamido): Nitrogen lone pairs donated into ring despite the amide carbonyl; net activating and ortho/para directing. (Activating: true, Deactivating: false, O/P: true, Meta: false) 8. -C(=O)NHCH3 (N-methylamide with carbonyl attached to ring): The carbonyl directly on ring is EWG by resonance withdrawal; deactivating, meta directing. (Activating: false, Deactivating: true, O/P: false, Meta: true) 9. -Br (bromo): Like fluorine, deactivating by induction but ortho/para directing by lone pair resonance. (Activating: false, Deactivating: true, O/P: true, Meta: false) 10. -CN (cyano): Strong EWG via resonance and induction. Deactivating, meta directing. (Activating: false, Deactivating: true, O/P: false, Meta: true) 11. -CF3 (trifluoromethyl): Strong EWG by induction (three F atoms). No lone pairs to donate. Deactivating, meta directing. (Activating: false, Deactivating: true, O/P: false, Meta: true) 12. -C(=O)NH2 (amide carbonyl on ring): Carbonyl directly attached to ring withdraws electrons. Deactivating, meta directing. (Activating: false, Deactivating: true, O/P: false, Meta: true) 13. -C(=O)OH (carboxylic acid, carbonyl on ring): EWG via carbonyl conjugation. Deactivating, meta directing. (Activating: false, Deactivating: true, O/P: false, Meta: true) 14. -CH=CH2 (vinyl): Conjugated EDG; lone pairs not involved but pi system donates electron density to ring ortho/para positions. Activating, ortho/para directing. (Activating: true, Deactivating: false, O/P: true, Meta: false) 15. -CH=CH-C(=O)OH (cinnamoyl acid type, conjugated with terminal carboxylic acid): The extended conjugation with the electron-withdrawing carboxylic acid makes the overall group EWG. Deactivating; the vinylogous EWG still places electron density withdrawal at ortho/para, but the answer given shows ortho/para directing (the vinyl portion can direct o/p even though deactivating overall, similar to halogens). (Activating: false, Deactivating: true, O/P: true, Meta: false) 16. -CH=CH-C(=O)H (cinnamaldehyde-type substituent): Similar to #15, the conjugated aldehyde makes it EWG/deactivating but the vinyl linkage means ortho/para directing character. (Activating: false, Deactivating: true, O/P: true, Meta: false) 17. -S-Et (ethylthio): Sulfur has lone pairs to donate (like oxygen in -OR), making it activating and ortho/para directing. (Activating: true, Deactivating: false, O/P: true, Meta: false) 18. -S(=O)-Et (sulfinyl): One oxygen on sulfur makes it partially EWG; deactivating but sulfur lone pairs still allow some ortho/para donation. Net: deactivating, ortho/para directing. (Activating: false, Deactivating: true, O/P: true, Meta: false) 19. -S(=O)2-Et (sulfonyl): Two oxygens on sulfur make it strongly EWG. Deactivating, meta directing (no lone pairs available for resonance donation). (Activating: false, Deactivating: true, O/P: false, Meta: true) 20. -N=O (nitroso): EWG (nitrogen withdraws), deactivating, but the lone pairs on nitrogen can donate into ortho/para positions, giving ortho/para direction despite deactivation. (Activating: false, Deactivating: true, O/P: true, Meta: false) 21. -CH2X (halomethyl, one halogen): The inductive EWG effect of the halogen through one CH2; deactivating and meta directing (no direct resonance donation to ring). (Activating: false, Deactivating: true, O/P: false, Meta: true) 22. -CHX2 (dihalomethyl, two halogens): Stronger inductive EWG than -CH2X; deactivating, meta directing. (Activating: false, Deactivating: true, O/P: false, Meta: true) Therefore, the correct answer is {"1": {"activating": true, "deactivating": false, "ortho_para": true, "meta": false}, "2": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "3": {"activating": true, "deactivating": false, "ortho_para": true, "meta": false}, "4": {"activating": true, "deactivating": false, "ortho_para": true, "meta": false}, "5": {"activating": false, "deactivating": true, "ortho_para": true, "meta": false}, "6": {"activating": true, "deactivating": false, "ortho_para": true, "meta": false}, "7": {"activating": true, "deactivating": false, "ortho_para": true, "meta": false}, "8": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "9": {"activating": false, "deactivating": true, "ortho_para": true, "meta": false}, "10": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "11": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "12": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "13": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "14": {"activating": true, "deactivating": false, "ortho_para": true, "meta": false}, "15": {"activating": false, "deactivating": true, "ortho_para": true, "meta": false}, "16": {"activating": false, "deactivating": true, "ortho_para": true, "meta": false}, "17": {"activating": true, "deactivating": false, "ortho_para": true, "meta": false}, "18": {"activating": false, "deactivating": true, "ortho_para": true, "meta": false}, "19": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "20": {"activating": false, "deactivating": true, "ortho_para": true, "meta": false}, "21": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}, "22": {"activating": false, "deactivating": true, "ortho_para": false, "meta": true}}.