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Common JEE question types and how to approach them:
Basicity order: In water, 2° > 1° > 3° > NH3 (aliphatic). Aromatic: -NH2 on ring is weakly basic (resonance). EWGs decrease, EDGs increase basicity. Always consider gas phase vs solution separately.
Identification: Use HNO2 (most informative), Hinsberg (systematic), carbylamine (specific for 1°). A primary aromatic amine gives stable diazonium (coupling possible); 1° aliphatic gives N2 gas.
Synthesis via diazonium: Identify the target functional group. If Cl/Br -> Sandmeyer. If F -> Balz-Schiemann. If I -> KI. If OH -> warm H2O. If H (deaminate) -> H3PO2. If CN -> Sandmeyer/CuCN.
Named reaction traps: (1) Gabriel can't make aniline but can make benzylamine. (2) Hofmann loses one carbon. (3) Carbylamine is for 1° only. (4) Direct nitration of aniline fails (oxidation). (5) Coupling requires correct pH (alkaline for phenol, weakly acidic for aniline).
Basicity traps: (1) Gas phase order is different from solution. (2) Pyridine > aniline (lone pair not in pi system). (3) Pyrrole is non-basic (lone pair IS in pi system). (4) Benzylamine behaves as aliphatic.