Building on the previous overview, this provides a more detailed chapter-wise breakdown for Organic Chemistry in CBSE Class 12 (Units 10-15 from NCERT). The analysis is derived from trends in previous year question papers (PYQs) from 2020-2025, including the 2025 paper which was rated easy to moderate overall, with organic sections being straightforward and NCERT-based. Organic Chemistry typically carries 28-33 marks (40-45% of the paper), with a focus on application, mechanisms, and conversions. Questions are spread across MCQs (1 mark), very short answers (VSA, 2 marks), short answers (SA, 3 marks), case-based (4 marks), and long answers (LA, 5 marks).
Repetition is high for core concepts (e.g., mechanisms appear in 5-6/6 years). Difficulty in 2025 was easy for organic (per student feedback from analyses), with no out-of-syllabus questions. Trends show increased case-based questions post-2022, emphasizing real-life applications (e.g., drug synthesis). For 2025, organic was ~33 marks, direct from NCERT, with predictable reactions like Aldol and Cannizzaro.
Nomenclature, isomerism (optical, positional), preparation (from alcohols, alkenes, hydrocarbons), reactions (SN1/SN2, E1/E2, nucleophilic substitution, elimination, reactions with metals like Wurtz), aryl halides (low reactivity, Friedel-Crafts failure), polyhalogen compounds (e.g., chloroform, iodoform), environmental impact (CFCs).
High; SN mechanisms and chirality repeat annually. In 2025, 6 marks (per analysis), with easy MCQs and SA on substitution.
Finkelstein, Swarts, Wurtz, Wurtz-Fittig, Sandmeyer (for aryl), Friedel-Crafts (failure in aryl halides). These appear in 4-5/6 years, often as 3-mark equations.
Common (80% papers); e.g., "Why is the boiling point of chloroethane higher than ethane?" (dipole-dipole); "Why do tertiary halides favor SN1?" (carbocation stability). Repetition: 5/6 years.
SN1 (carbocation intermediate, racemization), SN2 (backside attack, inversion), E1/E2 (base strength, Saytzeff rule). Detailed steps with arrows required in 3-5 mark questions; repeated in 5/6 years, e.g., 2023-2025 SN1 for tert-butyl chloride.
Classification (1°/2°/3° alcohols), nomenclature, preparation (hydration of alkenes, reduction of carbonyls, Grignard), reactions (dehydration to alkenes/ethers, oxidation, esterification, acidic nature of phenols, electrophilic substitution in phenols), ethers (Williamson synthesis, cleavage by HI), tests (Lucas, iodoform, ferric chloride for phenols).
High; dehydration and Williamson repeat often. In 2025, 6 marks, straightforward per feedback.
Williamson ether synthesis, Reimer-Tiemann (phenols to salicylaldehyde), Kolbe's (phenols to salicylic acid). Appear in 5/6 years, as 3-mark with conditions.
Frequent (90% papers); e.g., "Why are phenols more acidic than alcohols?" (resonance stabilization of phenoxide); "Why do ethers have lower boiling points?" (no H-bonding). Repeated 6/6 years.
Dehydration (E1 for 2°/3°, carbocation rearrangement), HI cleavage of ethers (SN2 for methyl, SN1 for tertiary), Reimer-Tiemann (carbene intermediate). Arrow-pushing required; repeated in 4-5/6 years, e.g., 2020-2025 dehydration.
Nomenclature, preparation (oxidation, ozonolysis, Friedel-Crafts acylation), reactions (nucleophilic addition: HCN, NH3 derivatives; aldol/cross-aldol, Cannizzaro, oxidation/reduction), carboxylic acids (acidity, esterification, decarboxylation, HVZ), tests (Tollens', Fehling's, iodoform).
Highest; aldol and iodoform in every paper. In 2025, 8 marks, easy with named reactions like Aldol/Cannizzaro.
Aldol condensation, Cannizzaro, Clemmensen, Wolff-Kishner, HVZ, Rosenmund, Etard, Haloform. Core repeats (6/6 years), often 3-5 marks with equations/mechanisms.
Common; e.g., "Why do aldehydes reduce Tollens' but ketones don't?" (alpha-H absence); "Why are carboxylic acids stronger than phenols?" (resonance). 6/6 years.
Nucleophilic addition (e.g., cyanohydrin), aldol (enolate attack), Cannizzaro (hydride transfer), HVZ (enol form). Detailed with intermediates; repeated annually, e.g., 2025 aldol.
Classification (1°/2°/3°), preparation (reduction of nitro, Gabriel, Hoffmann), basicity (aliphatic > aromatic), reactions (alkylation, acylation, carbylamine, diazotization, coupling), tests (Hinsberg, carbylamine).
Medium; basicity and Hinsberg repeat. In 2025, 6 marks, NCERT-based.
Gabriel phthalimide, Hoffmann bromamide, Sandmeyer (from diazonium), Azo coupling. 4/6 years, as 3-mark.
High; e.g., "Basicity order: 2° > 1° > 3° amines" (solvation, inductive); "Why aniline less basic?" (resonance). 5/6 years.
Diazotization (N2+ formation), Hinsberg (sulfonamide solubility). Less detailed, but repeated 4/6 years.
Carbohydrates (mono/di/poly, glucose structure, mutarotation, glycosidic linkages), proteins (primary/secondary/tertiary/quaternary, denaturation), enzymes (catalysis), vitamins (deficiencies), nucleic acids (DNA/RNA structure).
Medium; glucose and proteins repeat. In 2025, 7 marks (including polymers?), easy.
None major, but linkage formations (e.g., peptide, glycosidic).
Common; e.g., "Why is sucrose non-reducing?" (no free carbonyl); "Denaturation of proteins" (H-bond breaking). 4/6 years.
Rare; mutarotation (ring opening/closing) in 3/6 years.
Classification (addition/condensation, natural/synthetic), preparation (e.g., nylon-6,6, bakelite, PVC), biodegradable polymers (PHA, starch-based).
Low; nylon and biodegradable repeat occasionally. In 2025, possibly bundled with biomolecules (0-3 marks).
Condensation polymerizations (e.g., nylon from hexamethylenediamine/adipic acid).
"Difference between thermosetting/thermoplastic" (cross-linking); "Why biodegradable polymers?" (environmental). 3/6 years.
Polymerization steps (free radical for addition, condensation for others); rare, 2/6 years.
Focus on NCERT for 80% coverage; practice mechanisms with diagrams and conversions. High-repetition areas (aldol, SN, basicity) can fetch 15+ marks. Use PYQs from 2020-2025 for patterns—organic was easier in 2025 than 2023 (more twisted). Student feedback: Thorough NCERT study ensures full marks in organic.