OC-05 Five Core Bullets for Last-Minute Revision

PCC vs $KMnO_{4}$ : PCC stops 1° alcohol oxidation at aldehyde (anhydrous; no gem-diol formation); $KMnO_{4}$ / $K_{2}Cr_{2}O_{7}$ goes all the way to carboxylic acid (aqueous); 2° alcohol → ketone with either; 3° → no reaction.
Lucas test: $ZnCl_{2}$ /conc. HCl; 3° → immediate turbidity (SN1); 2° → 5-20 min; 1° → no turbidity at RT.
Phenol acidity: pKa ~10 (vs alcohol ~16); phenoxide resonance-stabilized; EWG (- $NO_{2}$ ) → more acidic; EDG (- $CH_{3}$ ) → less acidic.
Named reactions: Kolbe: P $hO^{-}$$Na^{+}$ + $CO_{2}$ , 125°C → salicylic acid (ortho-COOH); Reimer-Tiemann: PhOH + $CHCl_{3}$ /NaOH → salicylaldehyde (ortho-CHO) via : $CCl_{2}$ .
Williamson synthesis: $RO^{-}$$Na^{+}$ + R'X → ether; R'X MUST be 1° (2°/3° halides give E2 elimination, not ether).