Alcohols, phenols and ethers
Class 12 · Updated 2026-10-03. Published for practice.
Alcohols
Classification: 1°, 2°, 3° by carbon attached to –OH. Preparation: hydration of alkenes, hydroboration–oxidation (anti-Markovnikov alcohol), reduction of carbonyls, Grignard + carbonyl.
Oxidation: 1° → aldehyde → acid (controlled oxidation stops at aldehyde with some reagents); 2° → ketone; 3° resistant to mild oxidation. Lucas test (HCl + ZnCl2) distinguishes 1°/2°/3° by turbidity rate.
Phenols
Phenol is more acidic than alcohols (resonance-stabilised phenoxide). Less acidic than carboxylic acids. Reactions: electrophilic substitution (bromine water → white precipitate of 2,4,6-tribromophenol even without catalyst).
Reimer–Tiemann (salicylaldehyde from phenol), Kolbe (salicylic acid from phenoxide + CO2) — recognise names and one product each.
Ethers
Williamson synthesis: R–ONa + R′–X → R–O–R′ (SN2, best with primary halide). Ethers are weakly basic; cleavage with excess HI/HBr gives alkyl halides and alcohols stepwise.
Anisole and phenetole are intro aryl alkyl ethers; electrophilic substitution on the ring is the main chemistry NCERT emphasises for methoxybenzene.