Ch 11 covers alcohols (R-OH), phenols (Ar-OH), and ethers (R-O-R') — classification, preparation, physical and chemical properties, and important reactions.
Preparation: hydration of alkenes, reduction of aldehydes/ketones, Grignard reagent. Acidity order: phenol > water > 1° > 2° > 3° alcohol (in gas phase reversed). Phenol acidic due to resonance stabilisation of phenoxide ion. Reactions: dehydration (elimination), oxidation (1°→aldehyde→acid, 2°→ketone), ester formation.
Preparation: Williamson synthesis (R-X + R'ONa → R-O-R' + NaX, SN2 — use 1° alkyl halide). Properties: relatively unreactive, used as solvents. Reactions: cleavage by HI (weaker C-O bond breaks). Electrophilic substitution in anisole: -OCH₃ is activating, o/p directing.
Download: https://ncert.nic.in/textbook/pdf/lech202.pdf | Part II: https://ncert.nic.in/textbook/pdf/lech2ps.zip
Phenol is acidic because the phenoxide ion (C₆H₅O⁻) formed after losing H⁺ is stabilised by resonance — the negative charge delocalises over the benzene ring (5 resonance structures). In contrast, the alkoxide ion (RO⁻) from an alcohol has no such stabilisation. This makes phenol about 10⁶ times more acidic than ethanol (pKa 10 vs 16).
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