1. WRONG: "Benzene is more stable than cyclohexadiene only because of conjugation." CORRECT: Benzene's extra stability (resonance energy ≈36 kcal/mol) comes from FULL delocalization of all 6 pi electrons, not just conjugation between 2 double bonds. Cyclohexadiene has 2 conjugated double bonds but is much less stable than benzene.

2. WRONG: "Kekule structures are the actual structure of benzene." CORRECT: Kekule structures are resonance contributors. The actual structure is a hybrid with all C-C bonds equal (1.39 Å). Neither Kekule structure alone represents reality.

3. WRONG: "The arenium ion is stable and isolable." CORRECT: The arenium ion is a high-energy, reactive, non-aromatic carbocation intermediate. It is transient and loses $H^{+}$ rapidly (step 3) to restore aromaticity.

4. WRONG: "All deactivating groups are meta directors." CORRECT: Halogens (-F, -Cl, -Br, -I) are deactivating but ortho-para directors. Only deactivating groups with -M effect ($NO_{2}$, CN, CHO, COOH, COR) are meta directors. The halogen deactivation comes from -I; the directing comes from +M.

5. WRONG: "EAS of benzene follows Markovnikov's rule." CORRECT: Markovnikov's rule applies to addition reactions (HX addition to alkenes). EAS is a substitution reaction — the directing effects (o/p vs meta) are controlled by the existing substituents' electronic effects, not Markovnikov's rule.

6. WRONG: "FC Acylation can be performed on nitrobenzene." CORRECT: FC reactions fail on strongly deactivated rings. -$NO_{2}$ deactivates the ring so severely that the Lewis acid complex cannot form an effective electrophile for attack. FC reactions require at least a moderately activated or unactivated ring.

7. WRONG: "Sulfonation uses $H_{2}SO_{4}$ (not fuming $H_{2}SO_{4}$)." CORRECT: Standard (concentrated) $H_{2}SO_{4}$ does not sulfonation easily. Fuming $H_{2}SO_{4}$ (oleum, $H_{2}SO_{4}$ + $SO_{3}$) is required because $SO_{3}$ is the actual electrophile.

8. WRONG: "Protonated aniline (-$NH_{3}^{+}$) is still an o/p director." CORRECT: -$NH_{3}^{+}$ (protonated) has NO lone pair available for +M donation. It is now an electron-withdrawing group via -I, making it a META director and deactivating group — the opposite of free amine.

9. WRONG: "Pyridine undergoes EAS as readily as benzene." CORRECT: Pyridine's N is electron-withdrawing (the ring nitrogen is $sp^{2}$ hybridized and withdraws electron density from the ring via -I and -M effects). Pyridine is deactivated toward EAS and reacts 10^10 times slower than benzene. When EAS does occur, it goes to the 3-position (meta to N).

10. WRONG: "Resonance structures are in equilibrium and interconvert." CORRECT: Resonance structures are NOT in equilibrium. They are fictional Lewis representations of a single, real structure (the resonance hybrid). Electrons do NOT oscillate between resonance forms — the true electron distribution is a superposition.

11. WRONG: "Adding -$NH_{2}$ to a benzene ring makes it less reactive toward EAS." CORRECT: -$NH_{2}$ is the strongest activating group. Its lone pair donates into the ring (+M effect), greatly increasing electron density, especially at o/p positions. The ring is highly activated. In fact, aniline can react with $Br_{2}$ water WITHOUT a Lewis acid catalyst to give 2,4,6-tribromoaniline immediately.

12. WRONG: "The nitronium ion ($NO_{2}^{+}$) is generated by $HNO_{3}$ alone." CORRECT: $HNO_{3}$ alone cannot generate $NO_{2}^{+}$ efficiently. Conc. $H_{2}SO_{4}$ is required as a protonating agent: $H_{2}SO_{4}$ protonates $HNO_{3}$ → $H_{2}NO_{3}^{+}$ → $NO_{2}^{+}$ + $H_{2}O$. $H_{2}SO_{4}$ is the catalyst.

13. WRONG: "Toluene is less reactive than benzene toward EAS." CORRECT: Toluene is MORE reactive than benzene. The -$CH_{3}$ group is weakly activating (+I and hyperconjugation), increasing electron density at o/p positions. Nitration of toluene is faster than nitration of benzene.

14. WRONG: "Cyclopentadiene (neutral, $C_{5}H_{6}$) is aromatic." CORRECT: Neutral cyclopentadiene has an $sp^{3}$ $CH_{2}$ carbon which breaks full conjugation — one ring carbon does NOT have a p-orbital. It is non-aromatic. The cyclopentadienyl ANION ($C_{5}H_{5}^{-}$) is aromatic (the anion provides a lone pair to the p-orbital, completing conjugation: 6 pi electrons).

15. WRONG: "In sulfonation, the -$SO_{3}$H group cannot be removed once added." CORRECT: Sulfonation is the ONLY reversible EAS. Heating benzenesulfonic acid with dilute $H_{2}SO_{4}$ at high temperature reverses the reaction: Ar$SO_{3}$H → ArH + $H_{2}SO_{4}$. This reversibility is synthetically useful as a protecting group strategy for ring positions.

16. WRONG: "FC alkylation always gives a single monoalkyl product." CORRECT: FC alkylation gives polyalkylation because the monoalkyl product (e.g., toluene) is MORE reactive than the starting benzene (the alkyl group activates the ring). Multiple alkylations occur. FC acylation does NOT have this problem because the acyl group deactivates the ring.

17. WRONG: "Bond angles in benzene are 90° because of the hexagonal ring shape." CORRECT: All interior angles in a regular hexagon are 120°, and benzene's $sp^{2}$ hybridized carbons have 120° bond angles. This perfect match is part of why benzene is so stable — no ring strain.