Error 1 — The Halogen Trap (Most Tested) Students routinely state that halogens are meta directors because they are deactivating. This is WRONG. Halogens are ortho-para directors. The deactivating character (from -I) and the directing character (from +M to o/p) are independent properties. Chlorobenzene nitration gives o- and p-chloronitrobenzene as major products.

Error 2 — COT Called Anti-Aromatic COT has 8 pi electrons (4n), which satisfies the anti-aromatic electron count. However, anti-aromaticity requires planarity. COT is non-planar (tub shape), so it is non-aromatic, not anti-aromatic. The distinction matters: non-aromatic = neutral stability; anti-aromatic = actively destabilized.

Error 3 — FC Alkylation and Acylation Conflated Students forget which FC reaction rearranges and which gives polysubstitution. Mnemonic: "Alkylation is Awful" — both rearrangement and polyalkylation. "Acylation is Accurate" — neither problem. The key mechanistic reason is the resonance stabilization of the acylium ion (R$CO^{+}$), which prevents rearrangement, and the deactivating -COR product, which prevents polyacylation.

Error 4 — Sulfonation Forgetting Reversibility Only sulfonation is reversible. All other four EAS reactions (halogenation, nitration, FC alkylation, FC acylation) are irreversible under normal conditions. Sulfonation reversal requires heating with dilute $H_{2}SO_{4}$.

Error 5 — Counting Pyridine's Lone Pair as Pi Electrons Pyridine's N lone pair is in an $sp^{2}$ orbital in the ring plane — it does NOT contribute to the pi system. Pyridine has exactly 6 pi electrons, satisfying Huckel's rule as aromatic. Adding the lone pair to give 8 would be wrong and change the aromaticity classification.

Error 6 — Protonated Aniline Still Called Activating Free aniline (-$NH_{2}$) is strongly activating and o/p directing. Protonated aniline (-$NH_{3}^{+}$) has no available lone pair for +M donation. It becomes electron-withdrawing by -I and is a meta director and deactivating group — the complete opposite.