Exam prep · JEE Main, JEE Advanced, NEET
Organic Chemistry for JEE and NEET: Every NCERT Chapter, Mechanism by Mechanism
The organic chapters of the NCERT Class 11 and 12 textbooks, mapped to free mechanisms you draw yourself, one curved arrow at a time, with feedback on every move.
Why mechanisms matter for JEE and NEET
Organic chemistry is roughly a third of the chemistry paper in JEE Main, JEE Advanced and NEET. NEET questions mostly test whether you know the product of a reaction. JEE Advanced goes further: it gives you an unfamiliar substrate and asks what happens, which you can only answer by following the electrons.
A mechanism is that reasoning written down. Each curved arrow starts at a lone pair or a bond and ends where the new bond forms. Once the arrows make sense, the NCERT reactions stop being a list to memorise and become a handful of patterns: nucleophiles attack electron-poor carbon, carbocations rearrange to become more stable, leaving groups depart with their electron pair, and aromatic rings substitute rather than add.
The pages below are free. On each one you draw the mechanism yourself and get immediate feedback, the fastest way to find the step you do not yet understand.
Class 11: Organic Chemistry – Some Basic Principles and Techniques (GOC)
General organic chemistry is the foundation of every later chapter: inductive and resonance effects, hyperconjugation, the stability of carbocations, carbanions and free radicals, electrophiles and nucleophiles, and isomerism.
- Electron flow: how to draw a curved arrow
- Resonance and electron distribution
- Acid strength and the stability of conjugate bases
- Bonding, hybridisation and formal charge
- Carbocation stability and rearrangements
- Stereocentres and R/S configuration
- Enantiomers, diastereomers and meso compounds
- Conformations: Newman projections and chairs
- Functional groups and connectivity
Class 11: Hydrocarbons
Alkanes, alkenes, alkynes and benzene. The key mechanisms are electrophilic addition to alkenes (and when Markovnikov's rule is reversed), free-radical halogenation, and electrophilic substitution on benzene.
- Markovnikov addition of HCl to an alkene
- Peroxide effect (Kharasch): anti-Markovnikov HBr addition
- Addition of bromine: the bromonium ion
- Hydroboration–oxidation
- Cold dilute KMnO₄ (Baeyer's reagent)
- Ozonolysis of an alkene
- Hydration of an alkyne with HgSO₄/H₂SO₄
- Lindlar's catalyst: alkyne to cis-alkene
- Free-radical halogenation
- Nitration of benzene
- Halogenation of benzene with FeCl₃
- Sulphonation of benzene
- Friedel–Crafts alkylation
- Friedel–Crafts acylation
- Directive influence of substituents (ortho/para vs meta)
- Aromaticity and Hückel's rule
Class 12: Haloalkanes and Haloarenes
Nucleophilic substitution (SN1 and SN2), elimination, the stereochemistry of substitution, and why haloarenes resist nucleophilic substitution unless the ring carries electron-withdrawing groups.
- SN2: one step, with inversion of configuration
- SN1: carbocation intermediate and racemisation
- E2 elimination and Saytzeff (Zaitsev) rule
- E1 elimination
- Alcohol to alkyl chloride with SOCl₂
- Alcohol to alkyl bromide with PBr₃
- Finkelstein reaction
- Nucleophilic substitution in haloarenes (nitro groups activate)
- Why chlorine is ortho/para-directing but deactivating
- Optical activity, racemic mixtures and resolution
- Substitution vs elimination: exam-style problems
Class 12: Alcohols, Phenols and Ethers
Acid-catalysed dehydration, hydration of alkenes, reactions of phenol on the ring, and the preparation and cleavage of ethers.
- Acid-catalysed dehydration of alcohols
- Acid-catalysed hydration of alkenes
- Lucas test (ZnCl₂/HCl)
- Williamson ether synthesis
- Bromination of phenol
- Nitration of a phenol
- Reimer–Tiemann reaction
- Esterification of an alcohol
- Alcohols from Grignard reagents
- Alcohols by reduction of aldehydes and ketones
- Cleavage of C–O bonds in ethers and epoxides
- All alcohol reactions
Class 12: Aldehydes, Ketones and Carboxylic Acids
The largest organic chapter for both exams. Almost everything is nucleophilic addition to C=O, reactions at the α-carbon, or nucleophilic acyl substitution.
- Nucleophilic addition of HCN (cyanohydrins)
- Addition of sodium hydrogensulphite
- Hemiacetals and acetals
- Addition of ammonia derivatives (imines)
- Oxime formation
- Semicarbazone formation
- 2,4-DNP derivative
- Aldol condensation
- Cross aldol (Claisen–Schmidt) condensation
- Cannizzaro reaction
- Haloform (iodoform) reaction
- Hell–Volhard–Zelinsky reaction
- Wolff–Kishner reduction
- DIBAL-H: ester to aldehyde
- Gattermann–Koch reaction
- Esterification of carboxylic acids
- Acid chlorides to amides
- Ester hydrolysis (saponification)
- Acidity of carboxylic acids
Class 12: Amines
Basicity of amines, preparation (Gabriel, Hoffmann bromamide, reduction), the tests that tell primary, secondary and tertiary amines apart, and diazonium salts.
Class 12: Biomolecules
Glucose ring structures and mutarotation, glycosidic links, amino acids as zwitterions and the peptide bond.
NCERT named reactions: mechanisms at a glance
Every named reaction in the NCERT Class 11 and 12 organic chapters. Most have a curved-arrow mechanism you can practise. A few go by single-electron transfer at a metal surface or an electrode; for those, examiners ask for the reagents and product, so learn the equation.
| Named reaction | What it does | Practise the mechanism |
|---|---|---|
| Kolbe electrolysis | Carboxylate salts → alkane at the anode | Electron transfer, no curved-arrow mechanism: learn the equation |
| Wurtz reaction | R–X + Na → R–R | Electron transfer, no curved-arrow mechanism: learn the equation |
| Fittig and Wurtz–Fittig | Aryl and alkyl halides coupled by Na | Electron transfer, no curved-arrow mechanism: learn the equation |
| Markovnikov addition | HX adds H to the carbon with more H | HCl + 2-methylpropene |
| Kharasch (peroxide) effect | HBr + peroxide adds anti-Markovnikov | HBr, peroxide + hex-1-ene |
| Friedel–Crafts alkylation | Alkyl group onto benzene with AlCl₃ | Ethylation of benzene |
| Friedel–Crafts acylation | Acyl group onto benzene with AlCl₃ | Step-by-step mechanism |
| Finkelstein reaction | R–Cl/R–Br + NaI in acetone → R–I | Iodide exchange in acetone |
| Swarts reaction | R–Cl/R–Br + AgF or Hg₂F₂ → R–F | Not yet on Arrow Lab |
| Sandmeyer reaction | ArN₂⁺ + CuCl/CuBr/CuCN → ArCl/ArBr/ArCN | Electron transfer, no curved-arrow mechanism: learn the equation |
| Gattermann reaction (haloarenes) | ArN₂⁺ + Cu/HX → ArX | Electron transfer, no curved-arrow mechanism: learn the equation |
| Balz–Schiemann reaction | ArN₂⁺ BF₄⁻ + heat → ArF | Fluorobenzene |
| Williamson synthesis | Alkoxide + primary halide → ether | Step-by-step mechanism |
| Reimer–Tiemann reaction | Phenol + CHCl₃/NaOH → o-hydroxy aldehyde | 2-Naphthol formylation |
| Kolbe reaction (Kolbe–Schmitt) | Sodium phenoxide + CO₂ → salicylic acid | Not yet on Arrow Lab |
| Cumene process | Cumene hydroperoxide + acid → phenol + acetone | Not yet on Arrow Lab |
| Rosenmund reduction | RCOCl + H₂, Pd/BaSO₄ → RCHO | Not yet on Arrow Lab |
| Stephen reaction | RCN + SnCl₂/HCl, then H₂O → RCHO | Electron transfer, no curved-arrow mechanism: learn the equation |
| Etard reaction | Toluene + CrO₂Cl₂ → benzaldehyde | Not yet on Arrow Lab |
| Gattermann–Koch reaction | Benzene + CO/HCl, AlCl₃ → benzaldehyde | Formylation of toluene |
| Clemmensen reduction | C=O → CH₂ with Zn(Hg)/HCl | 1-Indanone to indane |
| Wolff–Kishner reduction | C=O → CH₂ with N₂H₄/KOH | Acetophenone to ethylbenzene |
| Tollens' and Fehling's tests | Aldehydes reduce Ag⁺ or Cu²⁺ | Electron transfer, no curved-arrow mechanism: learn the equation |
| Aldol condensation | Enolate adds to C=O, then loses water | Step-by-step mechanism |
| Cross aldol (Claisen–Schmidt) | Aromatic aldehyde + ketone | Benzalacetone |
| Cannizzaro reaction | Aldehyde without α-H → alcohol + carboxylate | Benzaldehyde |
| Haloform (iodoform) reaction | Methyl ketone + I₂/NaOH → CHI₃ + carboxylate | Acetone |
| Hell–Volhard–Zelinsky reaction | α-Halogenation of a carboxylic acid | Propanoic acid |
| Decarboxylation (soda lime) | RCOONa + NaOH/CaO → R–H | Not yet on Arrow Lab |
| Gabriel phthalimide synthesis | Primary amines from phthalimide | Alkylation and deprotection |
| Hoffmann bromamide degradation | RCONH₂ + Br₂/NaOH → RNH₂ (one carbon fewer) | Benzamide to aniline |
| Carbylamine reaction | 1° amine + CHCl₃/KOH → isocyanide | Not yet on Arrow Lab |
| Hinsberg's test | Benzenesulfonyl chloride tells 1°, 2° and 3° amines apart | Propylamine |
| Diazotisation | ArNH₂ + NaNO₂/HCl, 0–5 °C → ArN₂⁺ | 4-Methoxyaniline |
| Coupling reaction | ArN₂⁺ + phenol or aniline → azo dye | Phenoxide coupling |
Frequently asked questions
Is NCERT enough for organic chemistry in NEET?
For NEET, the NCERT Class 11 and 12 textbooks cover the syllabus, and most organic questions test reactions and named reactions that appear in them. Understanding the mechanisms behind those reactions makes them far easier to remember and to apply to unfamiliar compounds.
Which organic chapters carry the most weight in JEE?
General organic chemistry (GOC), hydrocarbons, haloalkanes and haloarenes, alcohols, phenols and ethers, aldehydes, ketones and carboxylic acids, and amines together account for most organic questions. Aldehydes, ketones and carboxylic acids is the largest single chapter.
Do I need to learn reaction mechanisms for JEE Advanced?
Yes. JEE Advanced regularly asks about intermediates, rearrangements, stereochemistry and the products of unfamiliar substrates. These questions are answered by following the electron movement, which is what a mechanism shows.
Why do the Wurtz, Sandmeyer and Kolbe electrolysis reactions have no curved-arrow mechanism here?
They go by single-electron transfer from a metal (sodium or copper) or at an electrode, through radicals, rather than by the two-electron movements that curved arrows show. For these reactions the exams ask for the reagents, conditions and products, so learn them as equations.
What is GOC in organic chemistry?
GOC stands for general organic chemistry, the NCERT Class 11 chapter Organic Chemistry – Some Basic Principles and Techniques. It covers inductive and resonance effects, hyperconjugation, the stability of reactive intermediates, electrophiles and nucleophiles, and isomerism, which every later reaction depends on.
Are these practice problems free?
Yes. Every mechanism and practice page linked from this guide is free to use, and on each one you draw the curved arrows yourself and get feedback on every step.
Start with one mechanism
Pick a chapter you are studying this week and draw its first mechanism. Each step tells you at once whether your arrow is right.
Sources
- National Council of Educational Research and Training (NCERT). Chemistry Part II, Textbook for Class XI; Chemistry Part II, Textbook for Class XII. ncert.nic.in
- National Testing Agency. Joint Entrance Examination (Main): information bulletin and syllabus. jeemain.nta.nic.in
- National Testing Agency. NEET (UG): information bulletin and syllabus. neet.nta.nic.in
- Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press, 2012.