# Alcohols, Phenols and Ethers, Class 12 Chemistry | SwaVid Alcohols, Phenols and Ethers, NCERT Class 12 Chemistry: notes with key ideas, formulas, common mistakes and 3 quick checks with worked answers. Canonical: https://www.swavid.com/cbse/class-12/chemistry/chapter/alcohols-phenols-and-ethers Source: https://www.swavid.com/cbse/class-12/chemistry/chapter/alcohols-phenols-and-ethers # Alcohols, Phenols and Ethers ## Formulas and definitions ## Key ideas ## Common mistakes ## Quick checks ## Keep going ## Questions parents ask ## Class 12 Chemistry on SwaVid ### Classification and nomenclature ### Preparation of alcohols and phenols ### Acidity of alcohols and phenols ### Reactions of alcohols ### Named reactions of phenols ### Preparation and cleavage of ethers ### Next chapter ### Related chapter ### All chapters SwaVid › CBSE › Class 12 › Chemistry › Alcohols, Phenols and Ethers Notes written by SwaVid from the NCERT textbook. Class 12 Chemistry, Unit 7. Key ideas, formulas and common mistakes. CBSE prints 6 marks for Unit 7, not for this chapter alone. Short answer. This chapter covers the classification, nomenclature, methods of preparation, physical properties, and chemical reactions of alcohols, phenols, and ethers. Students learn how the hydroxyl and alkoxy functional groups govern reactivity, acidity, and substitution pathways. Source: NCERT Chemistry Part II (Reprint 2026-27) , Unit 7, Alcohols, Phenols and Ethers Alcohols and phenols are classified as mono-, di-, tri- or polyhydric based on the number of -OH groups. Alcohols are further grouped into primary (1°), secondary (2°), and tertiary (3°) depending on the carbon bonded to the hydroxyl group. Ethers are classified as symmetrical (simple) or unsymmetrical (mixed) based on alkyl or aryl groups attached to oxygen. Alcohols are prepared by acid-catalysed hydration of alkenes, hydroboration-oxidation, and reduction of carbonyl compounds or esters using NaBH₄ or LiAlH₄. Phenols are commercially prepared from cumene via cumene hydroperoxide, or from chlorobenzene by fusion with NaOH, and from benzenesulphonic acid or diazonium salts. Phenols are noticeably more acidic than alcohols and water because the phenoxide ion is resonance-stabilised, dispersing the negative charge over the benzene ring. Electron-withdrawing groups (like -NO₂) increase phenol acidity, especially at ortho and para positions, while electron-releasing groups (like -CH₃) decrease it. Alcohols react as nucleophiles when the O-H bond breaks, as in esterification, and as electrophiles when the C-O bond breaks, as in reactions with hydrogen halides, PX₃, and SOCl₂. Acid-catalysed dehydration forms alkenes, following the order of ease: 3° > 2° > 1°. In the Kolbe reaction, sodium phenoxide reacts with CO₂ followed by acidification to produce salicylic acid (2-hydroxybenzoic acid). In the Reimer-Tiemann reaction, phenol reacts with chloroform in the presence of NaOH to introduce an aldehyde group at the ortho position, forming salicylaldehyde. Williamson ether synthesis involves an SN2 reaction of a primary alkyl halide with a sodium alkoxide or phenoxide. Ethers are cleaved by concentrated halogen acids like HI; with mixed ethers having a 3° alkyl group, the halide attacks the tertiary carbocation, forming a tertiary iodide. Try each question first. Then tap it to see the answer. Identify reaction: Hydroboration-oxidation adds H and OH across the alkene. The regioselectivity gives anti-Markovnikov hydration. CH₃-CH=CH₂ + [H₂O] → CH₃-CH₂-CH₂OH. Propan-1-ol Anisole is C₆H₅-O-CH₃. The phenyl-oxygen bond has partial double-bond character due to resonance and is stronger than the alkyl-oxygen bond. Protonation gives C₆H₅-O⁺(H)-CH₃; the I⁻ nucleophile attacks the methyl carbon via SN2. Products are C₆H₅OH and CH₃I. Phenol and iodomethane In aqueous medium, phenol readily ionises to phenoxide ion, which highly activates the ring. Bromination occurs at all available ortho and para positions. Phenol + 3 Br₂ (aq) → 2,4,6-Tribromophenol (white precipitate) + 3 HBr. 2,4,6-Tribromophenol Aldehydes, Ketones and Carboxylic Acids . Haloalkanes and Haloarenes . The 10 chapters of Class 12 Chemistry . CBSE does not give marks to one chapter. It prints 6 marks for Unit 7, Alcohols, Phenols and Ethers, which includes Alcohols, Phenols and Ethers. No. They are written by SwaVid from the NCERT textbook. The CBSE curriculum is the reference for what is assessed. Aldehydes, Ketones and Carboxylic Acids. SwaVid is an AI tutor for Indian students in Classes 6 to 12. It finds the earlier ideas a child missed, then teaches today’s chapter. Start free to see how it works. - Unit 7 NCERT book - 6 marks, Unit 7 - 3 quick checks - Using a tertiary alkyl halide in Williamson ether synthesis to make a mixed tertiary ether . Tertiary alkyl halides undergo elimination to give alkenes instead of substitution. Use a tertiary sodium alkoxide with a primary alkyl halide. - Predicting methyl alcohol when (CH₃)₃C-O-CH₃ is cleaved with one equivalent of HI . The reaction proceeds via an SN1 mechanism because a stable tertiary carbocation is formed, giving (CH₃)₃C-I and CH₃OH. - Treating phenol as less acidic than ethanol because both have an -OH group . Phenol is much more acidic than ethanol because the phenoxide ion is resonance-stabilised, while the ethoxide ion has no resonance and is destabilised by the +I effect of the ethyl group. - Expecting ortho-nitrophenol to have a higher boiling point than para-nitrophenol . Ortho-nitrophenol forms intramolecular hydrogen bonds, which prevents intermolecular association, giving it a lower boiling point and making it steam-volatile compared to para-nitrophenol. ## Key Links - [CBSE](https://www.swavid.com/cbse) - [Class 12](https://www.swavid.com/cbse/class-12) - [Chemistry](https://www.swavid.com/cbse/class-12/chemistry/chapters) - [Start free →](https://www.swavid.com/signup) - [All 10 chapters](https://www.swavid.com/cbse/class-12/chemistry/chapters) - [NCERT Chemistry Part II (Reprint 2026-27)](https://ncert.nic.in/textbook.php) - [Open notes](https://www.swavid.com/cbse/class-12/chemistry/chapter/aldehydes-ketones-and-carboxylic-acids) - [Open notes](https://www.swavid.com/cbse/class-12/chemistry/chapter/haloalkanes-and-haloarenes) - [Class 12 Chemistry](https://www.swavid.com/cbse/class-12/chemistry/chapters) - [Start free →](https://www.swavid.com/signup)