IIT JEE Advanced · NEET · Class XI–XII

Organic
Chemistry
Mastery

A comprehensive learning resource covering IUPAC nomenclature, all types of isomerism, reaction intermediates, electronic effects (inductive, resonance, hyperconjugation), and fundamental reaction types — crafted for top-tier competitive exam preparation.

IUPAC Naming

Structural Isomers

Carbocations & Carbanions

Resonance & Hyperconjugation

SN1, SN2, E1, E2

Named Reactions

Section 01

IUPAC Nomenclature

Systematic naming rules for organic compounds — the language of chemistry.

        Golden Rule
        IUPAC name = Substituents (prefix) + Longest chain (root) + Degree of unsaturation + Principal
          functional group (suffix)
      

Chain Length Prefixes (Root Words)

Carbons	Prefix	Example	IUPAC Name
1	Meth-	CH₄	Methane
2	Eth-	C₂H₆	Ethane
3	Prop-	C₃H₈	Propane
4	But-	C₄H₁₀	Butane
5	Pent-	C₅H₁₂	Pentane
6	Hex-	C₆H₁₄	Hexane
7	Hept-	C₇H₁₆	Heptane
8	Oct-	C₈H₁₈	Octane
9	Non-	C₉H₂₀	Nonane
10	Dec-	C₁₀H₂₂	Decane

Functional Group Suffixes

Functional Group	Suffix	Formula	Example
Alkane	-ane	C–C	Propane
Alkene	-ene	C=C	Propene
Alkyne	-yne	C≡C	Propyne
Alcohol	-ol	–OH	Propan-1-ol
Aldehyde	-al	–CHO	Propanal
Ketone	-one	C=O	Propan-2-one
Carboxylic Acid	-oic acid	–COOH	Propanoic acid
Amide	-amide	–CONH₂	Propanamide
Amine	-amine	–NH₂	Propylamine
Nitrile	-nitrile	–CN	Propanenitrile

Common Substituent Prefixes

Alkyl groups

–CH₃ → methyl
–C₂H₅ → ethyl
–C₃H₇ → propyl
–C₄H₉ → butyl
–CH(CH₃)₂ → isopropyl

Halogens

–F → fluoro
–Cl → chloro
–Br → bromo
–I → iodo

Other groups

–NO₂ → nitro
–NH₂ → amino
–OH → hydroxy
–OCH₃ → methoxy
–C₆H₅ → phenyl

Step-by-Step Naming Guide

Identify the Principal Functional Group

Use seniority order: COOH > SO₃H > COOR > COCl > CONH₂ > CN > CHO > C=O > OH > NH₂ > C=C > C≡C > Halogen. This group determines the suffix.

Select the Longest Carbon Chain

Choose the chain that contains the principal functional group and has the maximum carbon atoms. This is the parent chain (root word).

Number the Chain

Start numbering from the end that gives lowest locant to the principal functional group. In case of a tie, give lowest locant to the substituent appearing first alphabetically.

Name the Substituents

List substituents in alphabetical order (ignoring multiplying prefixes di-, tri-). Use di-, tri-, tetra- for identical groups. Complex substituents get parentheses.

Construct the Full Name

Locant-substituent(s)-root-locant-suffix e.g., 3-methylpentan-2-ol

Interactive IUPAC Naming Checker

Select a compound above to see its IUPAC name and analysis.

Section 02

Isomerism

Compounds with identical molecular formulae but different arrangements or spatial orientations.

Chain Isomerism

Compounds with the same molecular formula but different carbon skeleton (chain) arrangements.

Example: C₅H₁₂
              n-Pentane: CH₃–CH₂–CH₂–CH₂–CH₃

              Isopentane: CH₃–CH(CH₃)–CH₂–CH₃ (2-methylbutane)

              Neopentane: C(CH₃)₄ (2,2-dimethylpropane)

Physical properties (b.p., m.p.) differ. Branched isomers have lower boiling points due to reduced surface area.

Functional Group Isomerism

Same molecular formula but different functional groups, giving compounds from different homologous series.

Alcohols ↔ Ethers (C₂H₆O)
              CH₃CH₂OH (ethanol)

              CH₃–O–CH₃ (methoxymethane)
            

Aldehydes ↔ Ketones (C₃H₆O)
              CH₃CH₂CHO (propanal)

              CH₃COCH₃ (propan-2-one)
            

Carboxylic Acids ↔ Esters (C₂H₄O₂)
              HCOOCH₃ (methyl methanoate)

              CH₃COOH (ethanoic acid)
            

Alkenes ↔ Cycloalkanes (C₃H₆)
              CH₂=CHCH₃ (propene)

              △ (cyclopropane)
            

Position Isomerism

Same molecular formula and carbon chain, but functional group or substituent is at a different position.

Example: C₄H₉Cl
                1-Chlorobutane: CH₃CH₂CH₂CH₂Cl

                2-Chlorobutane: CH₃CH₂CHClCH₃

                1-Chloro-2-methylpropane: (CH₃)₂CHCH₂Cl

                2-Chloro-2-methylpropane: (CH₃)₃CCl

Geometric (Cis-Trans) Isomerism

Arises due to restricted rotation around C=C double bond. Condition: each carbon of the double bond must have two different groups.

              Condition for geometric isomerism
              Each C of C=C must bear two different substituents. If either carbon bears identical groups → no geometric
              isomers.
            

2-butene (CH₃CH=CHCH₃):
cis-2-butene: both CH₃ on same side (b.p. 3.7°C)
trans-2-butene: CH₃ on opposite sides (b.p. 0.9°C)

E/Z system (Cahn–Ingold–Prelog):
Z (zusammen) = same side of higher-priority groups
E (entgegen) = opposite sides of higher-priority groups

              JEE Key Point
              Cis isomers generally have higher b.p. (polarity) but lower m.p. than trans isomers. Trans isomers are
              more symmetric → higher m.p., more stable.
            

Optical Isomerism

Compounds that rotate plane-polarized light. Requires a chiral carbon (sp³ carbon with 4 different groups attached).

Key Terms

Enantiomers

Non-superimposable mirror images. Rotate PPL equally but in opposite directions. Identical physical properties except optical rotation.

Diastereomers

Stereoisomers that are NOT mirror images. Different physical properties. Includes cis-trans isomers.

Meso Compounds

Has chiral centers but is optically inactive due to internal plane of symmetry. Achiral molecule overall.

R/S Configuration (CIP Rules)

Assign priorities

Higher atomic number → higher priority. If tie, go to next atom. Phantom atoms for multiple bonds.

Orient molecule

Place lowest priority group (4) away from you (going into page).

Trace 1→2→3

Clockwise → R (rectus). Anticlockwise → S (sinister).

Place lowest priority group (4) away from you (going into page. On the otherhand 4th priority wedge position towards you, then the clockwise system indicates S-Isomer

                  Formula
                  Max. optical isomers = 2ⁿ (n = no. of chiral carbons)

                  Meso compounds reduce this number.
                

Tautomerism

Dynamic interconversion between two isomers, usually involving proton transfer and shift of a double bond. Most common: keto-enol tautomerism.

Keto ⇌ Enol tautomerism:

CH₃–C(=O)–CH₃ ⇌ CH₃–C(OH)=CH₂
(acetone: keto) (enol form, minor)

Acetylacetone: 80% enol (stabilized by resonance + H-bonding)
Glucose: α and β forms (mutarotation)

              JEE Key Point
              Tautomers are in equilibrium, interconverting via proton transfer (acid/base catalysis). They
              differ from resonance structures — tautomers are real, separate molecules with finite lifetime.
            

Section 03

Reaction Intermediates

Short-lived, high-energy species formed and consumed during organic reactions.

⊕

Carbocation (Carbenium Ion)

Electron deficient

Carbon with only 3 bonds and an empty p-orbital. Has a positive charge. sp² hybridized, planar geometry.

R₃C⁺ (tertiary = most stable)
R₂CH⁺ (secondary)
RCH₂⁺ (primary = least stable)
CH₃⁺ (methyl = very unstable)

            Stability Order
            3° > 2° > 1° > methyl

            Allylic ≈ 3° > Benzylic ≈ 3°

            Stabilized by: +I, hyperconjugation, resonance

            JEE Trick
            Allyl cation (CH₂=CH–CH₂⁺) stabilized by resonance with vinyl group. Cyclopentadienyl cation has 4π
            electrons — antiaromatic, highly unstable!
			
          

⊖

Carbanion

Electron rich

Carbon with 3 bonds + lone pair. Has a negative charge. Generally sp³ hybridized (pyramidal) unless stabilized.

CH₃⁻ (methyl = most stable carbanion)
RCH₂⁻ (primary)
R₂CH⁻ (secondary)
R₃C⁻ (tertiary = least stable)

            Stability Order (opposite to carbocations!)
            methyl > 1° > 2° > 3°

            Stabilized by: –I effect, resonance, adjacent π system, sp hybridization
          

            Key Example
            Acetylide anion (R–C≡C⁻): sp hybridized, very stable due to high s-character (50%) → strongly
            electronegative carbon
          

•

Free Radical

Unpaired electron

Carbon species with one unpaired electron and three bonds. sp² hybridized, planar. Neutral but highly reactive.

R₃C• (tertiary radical = most stable)
R₂CH• (secondary radical)
RCH₂• (primary radical)
•CH₃ (methyl radical)

            Stability Order
            3° > 2° > 1° > methyl

            Allyl > benzyl > 3° > 2° > 1°

            Stabilized by hyperconjugation and resonance

Formed by: homolytic cleavage (heat, UV, peroxides). React via chain mechanism: initiation → propagation → termination.

Carbene & Nitrene

Neutral, 2-bond

Carbene: carbon with only TWO bonds and two non-bonding electrons. Extremely reactive.

:CH₂ (methylene carbene)
:CCl₂ (dichlorocarbene)

Singlet carbene: spin-paired, sp² (electrophilic)
Triplet carbene: spin-parallel, sp² + p (radical-like)

            Nitrene
            :NH species — nitrogen analogue of carbene. Formed from azides (R–N₃ →Δ R–N: + N₂). Used in Curtius
            rearrangement.
          

Comparative Summary of Intermediates

Property	Carbocation	Carbanion	Free Radical	Carbene
Charge	+1	–1	0	0
Bonding electrons	6 (3 bonds)	8 (3 bonds + LP)	7 (3 bonds + 1e⁻)	4 (2 bonds + 2e⁻)
Hybridization	sp²	sp³ (usually)	sp²	sp²/sp
Geometry	Planar (trigonal)	Pyramidal	Planar	Bent
Stability increases with	+I, resonance, hyperconj	–I, resonance, sp char.	Hyperconj, resonance	Electroneg. substituents
Cleavage type	Heterolytic	Heterolytic	Homolytic	α-elimination

Intermediate Stability Analyzer

Select type and structure to analyze stability and properties.

Section 04

Electronic Effects

How electrons are distributed through bonds and influence reactivity and stability.

Inductive Effect (I-effect)

Transmitted through σ-bonds

Displacement of σ-bond electrons due to electronegativity difference. Decreases rapidly with chain length.

              +I Effect (electron donating)
              Pushes electrons toward the reference carbon.

              –CH₃ > –C₂H₅ > –C₃H₇ > –C(CH₃)₃

              Metal-C bonds: –MgX, –Li also +I

              –I Effect (electron withdrawing)
              Pulls electrons away from chain.

              –F > –OH > –NH₂ > –Br > –Cl > –I

              –NO₂ > –CN > –CHO > –COOH > –COOR

              Application
              Strength of acids: +I groups weaken acidity; –I groups strengthen acidity.

              Formic acid > Acetic acid (CH₃ is +I, reduces acidity)
            

Resonance (Mesomeric) Effect

Delocalization through π-bonds

Delocalization of π-electrons or lone pairs over conjugated systems. Operates over longer distances than inductive effect.

              +M Effect (electron donating by resonance)
              Groups with lone pairs adjacent to π-system donate electrons.

              –NH₂ > –OH > –OR > –F > –Cl > –Br > –I
            

              –M Effect (electron withdrawing by resonance)
              Groups with π-bonds withdraw electrons.

              –NO₂ > –CN > –CHO > –COOH > –SO₃H
            

Aniline: NH₂ donates e⁻ to ring by +M
Nitrobenzene: NO₂ withdraws e⁻ from ring by –M
Phenol: OH is +M → activates ortho/para positions

Hyperconjugation

No-bond resonance / σ-π delocalization

Delocalization of σ-bonding electrons (C–H bonds of alkyl groups) into adjacent empty p-orbital or π-system. Also called "Baker-Nathan effect."

              Key Principle
              More α-hydrogens → more hyperconjugation → greater stability

              (CH₃)₃C⁺: 9 α-H → most stable 3° carbocation

              (CH₃)₂CH⁺: 6 α-H → 2° carbocation

              CH₃CH₂⁺: 3 α-H → 1° carbocation

CH₃–CH=CH₂ ↔ ⁺CH₂–CH=CH₂ (no-bond resonance)
The C–H bond partially overlaps with empty p-orbital of C⁺
or π* of double bond, delocalizing electron density.

              Applications
              1. Stability of carbocations and free radicals

              2. Stability of alkenes (more substituted = more stable)

              3. Acidic character of C–H bonds adjacent to π-system

              4. Ortho/para directing nature of alkyl groups on benzene

Electromeric Effect

Reagent-induced π-electron transfer

Complete transfer of π-electrons from one atom to another in the presence of a reagent. Temporary effect — occurs only when the reagent approaches.

              +E Effect
              π-electrons transferred toward the attacking electrophile's carbon.

              C=C + E⁺ → transfer toward E⁺
            

              –E Effect
              π-electrons transferred away from the attacking nucleophile's carbon.

              C=O + Nu:⁻ → transfer away from Nu⁻
            

              Comparison with Resonance
              Resonance: permanent delocalization, exists even without reagent.

              Electromeric: temporary, only when reagent attacks.
            

Hyperconjugation — Count α-Hydrogens

Select a species to count α-hydrogens and analyze hyperconjugative stabilization.

Electronic Effects — Comparative Overview

Effect	Type of Bond	Permanent/Temporary	Range	Requires Reagent
Inductive (I)	σ-bond	Permanent	Short (decreases with distance)	No
Resonance/Mesomeric (M)	π-bond / lone pair	Permanent	Through conjugation	No
Hyperconjugation	σ C–H into π	Permanent	Adjacent position	No
Electromeric (E)	π-bond	Temporary	Within molecule	Yes

Section 05

Basic Reaction Types

Classification of organic reactions by bond-making and bond-breaking mechanisms.

Substitution Reactions

One atom/group is replaced by another.

SN1 (Unimolecular Nucleophilic)

Step 1: R–X → R⁺ + X⁻ (slow, rate-determining)
Step 2: R⁺ + Nu:⁻ → R–Nu (fast)

Rate = k[R–X] (first order)
Favored: 3° > 2° substrates
Solvent: polar protic
Stereochemistry: racemization

                  Memory Aid
                  SN1: "one substrate decides the rate" → unimolecular. Forms carbocation → planar → racemization.
                

SN2 (Bimolecular Nucleophilic)

Nu:⁻ + R–X → [Nu···R···X]‡ → Nu–R + X⁻
(One concerted step — backside attack)

Rate = k[R–X][Nu⁻] (second order)
Favored: methyl > 1° > 2° >> 3°
Solvent: polar aprotic (DMSO, DMF)
Stereochemistry: inversion (Walden inversion)

                  Memory Aid
                  SN2: "two species in rate law" → bimolecular. Backside attack → 100% inversion (umbrella flip).
                

Electrophilic Aromatic Substitution (EAS)

ArH + E⁺ → Ar–E + H⁺

Mechanism: Attack of E⁺ → Arenium ion (σ-complex) → Deprotonation → Substituted product

Examples: Halogenation (X₂/FeX₃), Nitration (HNO₃/H₂SO₄), Sulfonation (H₂SO₄),
Friedel-Crafts Alkylation (R–X/AlCl₃), Friedel-Crafts Acylation (RCOCl/AlCl₃)

Addition Reactions

Two reactants combine to form a single product. Common in alkenes, alkynes, carbonyls.

Electrophilic Addition (to C=C)

HBr + CH₂=CH₂ → CH₃CH₂Br

Mechanism:
Step 1: H⁺ attacks π-bond → carbocation
Step 2: Br⁻ attacks carbocation

Markovnikov's Rule:
H adds to C with more H atoms (H to the H-rich carbon).
Anti-Markovnikov: with peroxide (free radical mechanism)

Nucleophilic Addition (to C=O)

Nu:⁻ + R–CHO → R–CH(OH)–Nu

Nu attacks electrophilic carbon of C=O:
Aldehydes > Ketones (steric effect)

Examples:
HCN + RCHO → Cyanohydrin
NaHSO₃ + RCHO → Bisulfite adduct
RMgX + C=O → Alcohol (Grignard)

              Ozonolysis & Catalytic Hydrogenation
              Alkene + O₃ → ozonide → (Zn/H₂O) → aldehyde/ketone

              Alkene + H₂ → (Pt/Pd/Ni, heat) → Alkane (syn addition, cis product from cis-alkene)
            

Elimination Reactions

Removal of atoms/groups from adjacent carbons to form a π-bond (alkene or alkyne).

E1 (Unimolecular Elimination)

Step 1: R–X → R⁺ + X⁻ (slow)
Step 2: Base removes β-H → alkene (fast)

Rate = k[R–X]
Favored: 3° substrate, weak base, polar protic
Follows Saytzeff's Rule:
More substituted alkene preferred

E2 (Bimolecular Elimination)

Base removes β-H simultaneously with C–X breaking
(concerted one-step mechanism)

Rate = k[R–X][Base]
Requires anti-periplanar geometry (β-H and X are anti)
Strong bulky base (t-BuOK) → Hofmann product (less substituted alkene)
Normal strong base → Saytzeff product

              Competition: SN vs E
              High temperature → Elimination favored

              Strong bulky base → E2 over SN2

              3° substrate + weak nucleophile → SN1 or E1

              Saytzeff's rule: more substituted (more stable) alkene forms preferentially in E1 and E2 (with non-bulky
              base)
            

Rearrangement Reactions

Migration of a group or hydride from one atom to an adjacent atom, usually to form a more stable intermediate.

Occurs in SN1 and E1 reactions when a more stable carbocation can be formed.

(CH₃)₂CHCH₂⁺ → [1,2-hydride shift] → (CH₃)₂C⁺CH₃
(primary → tertiary carbocation)

Neopentyl system: (CH₃)₃C–CH₂⁺ → 1,2-methyl shift → (CH₃)₂C⁺–CH₂CH₃
(explains rearrangement products in solvolysis)

Vicinal diol (pinacol) → ketone (pinacolone) under acid catalysis.

(CH₃)₂C(OH)–C(OH)(CH₃)₂ →(H⁺)→ (CH₃)₃C–CO–CH₃
Protonation → 3° carbocation → 1,2-methyl shift → oxocarbenium → ketone

Beckmann: Oxime → amide (lactam) under acid
The group anti to –OH migrates.

R–C(=NOH)–R' →(H₂SO₄)→ R–CO–NHR' (amide)

Baeyer–Villiger: Ketone → ester/lactone with peroxide (mCPBA)
More substituted group migrates preferentially.

R–CO–R' + peracid → R–COO–R' (ester)
Migration order: H < methyl < primary < secondary < tertiary ≈ phenyl

Oxidation–Reduction

Key Oxidizing Agents

KMnO₄

KMnO₄ (acidic/basic)

Cold dilute: cis-diol formation from alkene
Hot conc.: cleavage → ketone/acid/CO₂

O₃

Ozonolysis (O₃)

Oxidative: O₃ then H₂O₂ → carboxylic acids
Reductive: O₃ then Zn/H₂O → aldehydes/ketones

CrO₃

PCC / CrO₃

PCC: 1° alcohol → aldehyde (stops here)
CrO₃/H₂SO₄: 1° → carboxylic acid

Key Reducing Agents

LiAlH₄

LiAlH₄ (LAH)

Reduces all carbonyl groups, esters, amides, nitriles, carboxylic acids → alcohols or amines. Cannot reduce C=C.

NaBH₄

Milder — reduces aldehydes and ketones only. Leaves esters, carboxylic acids, amides intact.

H₂

Catalytic Hydrogenation

Pt/Pd/Ni: C=C → C–C, C≡C → C=C or C–C (syn addition). Lindlar's catalyst: alkyne → cis-alkene only.

Section 06

Named Reactions

Essential named reactions for IIT JEE Advanced and NEET.

2 CH₃CHO → NaOH, Δ → CH₃CH(OH)CH₂CHO → CH₃CH=CHCHO + H₂O

Mechanism: Base abstracts α-H → enolate → nucleophilic addition to carbonyl → β-hydroxy aldehyde (aldol product) → dehydration (above 65°C) → α,β-unsaturated carbonyl (crotonaldehyde)

                JEE Key
                Cross aldol with two different carbonyl compounds gives a mixture of 4 products. Mixed aldol is useful
                only when one component lacks α-H (e.g. HCHO, benzaldehyde).
              

2 Benzaldehyde → conc. NaOH → CARBOXYLIC ACID + ALCOHOL

This redox disproportionation of non-enolizable aldehydes to carboxylic acids and alcohols is conducted in concentrated base..

R–X + Mg dry ether → R–MgX → + C=O → R–C–OH

R–MgX is a powerful nucleophile and base. Reacts with HCHO → 1° alcohol; RCHO → 2° alcohol; R₂CO → 3° alcohol; CO₂ → carboxylic acid; ester → 3° alcohol. Must use dry ethereal solvent (reacts violently with water).

Diene (s-cis) + Dienophile → Δ or Lewis acid → Cyclohexene

Concerted [4+2] cycloaddition. Diene must be in s-cis conformation. Dienophile is electron-poor (–CHO, –CN, –COOH). Syn addition — cis groups on diene end up cis in product. Stereospecific (endo/exo).

                Endo Rule
                Endo product is kinetically preferred (secondary orbital interactions). Exo product is thermodynamically
                preferred.
              

ArCHO + (RCO)₂O RCOONa, Δ → ArCH=CR–COOH + RCOOH

The Perkin reaction involves reacting a non-enolizable aldehyde with an acid anhydride such as acetic anhydride in the presence of a weak base to form an α, β-unsaturated acid. The base deprotonates the anhydride to form a carbanion which then attacks the aldehyde, forming an alkoxide ion. An internal transfer of the acetyl group occurs via a cyclic intermediate, and removal of an α-hydrogen leads to loss of the carboxylate leaving group, yielding the anion of the α, β-unsaturated acid product..

PhONa + CO₂ 125°C, 4–7 atm → o-Hydroxybenzoate (sodium salicylate)

PhOH + CHCl₃ aq. NaOH, Δ → o-Hydroxybenzaldehyde (salicylaldehyde)

Kolbe's synthesis: Electrophilic attack by CO₂ on phenoxide ion at ortho position. Product: salicylic acid (aspirin precursor).

Reimer–Tiemann: Dichlorocarbene (:CCl₂) generated from CHCl₃/NaOH acts as electrophile. Introduces CHO at ortho position of phenol.

Kolbe and Reimer-Tiemann reaction diagram

Ar-N2Cl salt → Cu-X → Ar-X + N2 gas

The Sandmeyer reaction is a type of substitution reaction that is widely used in the production of aryl halides from aryl diazonium salts. In this process, we deal with Copper salts like chloride, bromide, or iodide ions that act as a catalyst in this reaction .

Ar + R-Cl → AlCl3 → Ar-R

When an aromatic ring reacts with an alkyl halide (such as methyl chloride) in the presence of AlCl₃, the catalyst pulls the halogen away, forming a carbocation. The electron-rich aromatic ring then attacks this carbocation, forming a new carbon-carbon bond

RCOCl+AlCl3 → Ar /Benzene → Ar-CO-R

Friedel-Crafts acylation is an electrophilic aromatic substitution reaction that attaches an acyl group (a carbonyl group bonded to an alkyl group) to an aromatic ring, such as benzene. It relies on a Lewis acid catalyst (like AlCl₃) to generate a highly reactive acylium ion from an acyl chloride or anhydride.

friedelcrafts acylation reaction diagram

Ar-NH2 → NaNO2 + HCl → Ar-N2Cl Diazonium Salt

The diazotization reaction is a chemical reaction that converts a primary aromatic amine into a diazonium salt.

Benzene → Li/NH3 or Na/NH3 Ethanol → Diene

Birch reduction is an organic redox reaction that is used to convert an aromatic compound into a diene. The reaction is carried out by sodium or potassium metal dissolved in liquid ammonia in the presence of alcohol.

CH3CHO → Zn/HCl → CH3-CH3

The reduction of aldehydes and ketones into corresponding hydrocarbon on treatment with zinc amalgam and concentrated hydrochloric acid.

CH3CHO + NH2-NH2 → Hydrazone → CH3-CH3

The Wolff-Kishner reduction is a chemical reaction used to convert aldehydes or ketones into alkanes, completely removing the carbonyl oxygen and replacing it with two hydrogen atoms (C=O → CH₂). The key components involved are hydrazine, a strong base, and a high-boiling solvent

2 CH3 → 2Na → CH3-CH3+ 2NaBr

The Wurtz reaction is a coupling reaction where two alkyl halides react with sodium metal in dry ether to form a higher symmetrical alkane and sodium halide.

2 Ar-CHO → KCN → BENZOIN

The Benzoin Condensation (or Benzoin reaction) is a combination of two aldehydes to form a new C-C bond, often catalyzed by cyanide ion.

METHYL KETONE + I2/NaOH → ACID WORKUP → CARBOXYLATE ION + CHX3

The Haloform Reaction is a very specific type of alpha halogenation reaction. This reaction takes place at the methyl ketone turning the methyl into a good haloform leaving group. This can include chloroform and bromoform, and of course the Iodoform solid precipitate used in lab to test for the presence of a methyl ketone.

→ →

In organic chemistry, an oxidation reaction is a process that increases the number of bonds to oxygen atoms or decreases the number of carbon-hydrogen (C-H) bonds

2 HCHO → conc. NaOH → CH₃OH + HCOONa

WILL BE UPDATED SOON.

→ →

Aromaticity is a property of conjugated cycloalkenes in which the stabilization of the molecule is enhanced due to the ability of the electrons in the orbitals to delocalize. This act as a framework to create a planar molecule..

2 HCHO → conc. NaOH → CH₃OH + HCOONa

WILL BE UPDATED SOON

Section 07

Quick Practice Quiz

Test your understanding — IIT JEE style questions.

Q 1 of 8

Score: 0

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Section 08

Quick-Reference Summary

At-a-glance overview of key concepts for revision.

Key Stability Orders & Memory Tricks

CARBOCATION STABILITY:
3° > 2° > 1° > methyl
Allylic ≈ Benzylic > 3°
Cyclopentadienyl cation → antiaromatic (UNSTABLE)
Cycloheptatrienyl cation → aromatic (STABLE)
──────────────────────────────
CARBANION STABILITY:
methyl > 1° > 2° > 3°
sp > sp² > sp³ (s-character increases stability)
Adjacent EWG stabilize; EDG destabilize
──────────────────────────────
FREE RADICAL STABILITY:
3° > 2° > 1° > methyl
Allyl > Benzyl > 3° > 2° > 1°

ACID STRENGTH:
EWG (–I, –M) → increase acidity
EDG (+I, +M) → decrease acidity
HCOOH > CH₃COOH > C₂H₅COOH
Cl₃CCOOH >> CCl₂HCOOH > CClH₂COOH
──────────────────────────────
BASE STRENGTH (amines in water):
R₂NH > RNH₂ > R₃N > NH₃ > ArNH₂
p-NO₂–C₆H₄–NH₂ is weakest amine
──────────────────────────────
ALKENE STABILITY (Zaitsev):
More substituted > less substituted
Trans > cis (same substitution)

Reaction Mechanism Flowchart — Which Mechanism Operates?

Conditions	Mechanism	Stereochemistry	Product Rule
3° substrate + weak nucleophile, polar protic	SN1	Racemization	Rearrangement possible
Methyl/1° substrate + strong nucleophile, polar aprotic	SN2	Inversion (100%)	No rearrangement
3° substrate + weak base, polar protic, heat	E1	—	Saytzeff (more substituted)
Any substrate + strong base, anti-periplanar geometry	E2	Anti elimination	Saytzeff (or Hofmann with bulky base)
Alkene + HX, no peroxide	AE (Markov.)	Addition to stable carbo-cation	Markovnikov product
Alkene + HBr + peroxide	AR (Radical)	—	Anti-Markovnikov product
Ar–H + E⁺, Lewis acid catalyst	EAS	—	Ortho/para or meta depending on ring activation

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IUPAC Nomenclature

Isomerism

Reaction Intermediates

Electronic Effects

Basic Reaction Types

Named Reactions

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