GOC-2 Reactive Intermediates & Mechanism: Complete Guide & Formula Sheet with Free PDF Download (JEE & NEET)
GOC-2 Reactive Intermediates & Mechanism — Competishun
GOC-2 Reactive Intermediates & Mechanism: Complete Guide & Formula Sheet with Free PDF Download (JEE & NEET)
Carbocation · Carbanion · Free Radical · Carbene · Nitrene · Benzyne · SN1 · SN2 · E1 · E2
GOC-2 (General Organic Chemistry - Part 2) is the study of reactive intermediates and reaction mechanisms. It explains how organic reactions occur at the molecular level, what intermediates are formed, and how they determine the outcome of a reaction. This chapter is the bridge between the basic concepts of GOC-1 and the complex reaction mechanisms of organic chemistry.
Every organic reaction proceeds through one or more reactive intermediates. Understanding their formation, structure, stability, and reactivity is essential for predicting reaction products and understanding reaction mechanisms. From carbocations and carbanions to free radicals, carbenes, nitrenes, and benzynes, each intermediate has its own unique characteristics.
This page gives you the complete guide to GOC-2 Reactive Intermediates & Mechanism with all concepts explained in depth. You will find clear definitions, stability orders, tables of reactions, mechanism comparisons, and practice questions. Download the free PDF below and keep it handy for quick revision before your JEE Main, JEE Advanced, or NEET exam.
Carbocationsp² · Planar · 6 e⁻
Carbanionsp³ · Pyramidal · 8 e⁻
Free Radicalsp² · Planar · 7 e⁻
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What is GOC-2 in Organic Chemistry?
Definition: GOC-2 (General Organic Chemistry - Part 2) is the study of reactive intermediates and reaction mechanisms. It covers the formation, structure, stability, and reactions of carbocations, carbanions, free radicals, carbenes, nitrenes, and benzynes. It also includes the concepts of electrophiles and nucleophiles, and the mechanisms of substitution (SN1, SN2) and elimination (E1, E2) reactions.
GOC-2 Reactive Intermediates & Mechanism is the foundation for understanding how organic reactions actually happen. Without this knowledge, organic chemistry becomes a collection of reactions to memorise rather than a logical system to understand.
Reactive Intermediates
Short-lived species formed during the course of a reaction. Their stability determines the pathway and products of the reaction.
Reaction Mechanisms
The step-by-step sequence of events that occurs during a reaction. Understanding mechanisms allows you to predict products and reaction conditions.
Key Insight: GOC-2 Reactive Intermediates & Mechanism is the bridge between the structure of molecules (GOC-1) and their reactivity. Understanding intermediates and mechanisms allows you to predict the outcome of any organic reaction.
Glossary of GOC-2 Terms — Complete A to Z
Before diving deep into each topic, let's understand the key terminology used in GOC-2 Reactive Intermediates & Mechanism:
| Term | Definition |
|---|---|
| Reactive Intermediate | A short-lived, high-energy species formed during the course of a reaction. It is neither the reactant nor the product. |
| Carbocation | A positively charged carbon species with six electrons in its valence shell (sextet). sp² hybridised and planar. |
| Carbanion | A negatively charged carbon species with eight electrons in its valence shell (octet). sp³ hybridised and pyramidal. |
| Free Radical | A neutral carbon species with seven electrons in its valence shell (one unpaired electron). sp² hybridised and planar. |
| Carbene | A neutral divalent carbon species with six electrons in its valence shell. Highly reactive. |
| Nitrene | A neutral monovalent nitrogen species with six electrons in its valence shell. Highly reactive. |
| Benzyne | A neutral, highly reactive species with a triple bond in a benzene ring (also called aryne). |
| Electrophile | An electron-deficient species that seeks electrons (electron lover). Accepts a pair of electrons to form a bond. |
| Nucleophile | An electron-rich species that seeks positive centres (nucleus lover). Donates a pair of electrons to form a bond. |
| Leaving Group | A group that departs with a pair of electrons during a substitution or elimination reaction. Good leaving groups are weak bases. |
| Mastering these terms is essential for understanding GOC-2 Reactive Intermediates & Mechanism. They will be used throughout this guide. | |
Reactive Intermediates — The Heart of GOC-2
Definition: Reactive intermediates are short-lived, high-energy species formed during the course of a reaction. They are neither the reactants nor the products, and they react further to give the final products.
The most common reactive intermediates in organic chemistry are:
| Intermediate | Charge | Valence Electrons | Hybridisation | Geometry |
|---|---|---|---|---|
| Carbocation | Positive (+) | 6 (sextet) | sp² | Planar |
| Carbanion | Negative (-) | 8 (octet) | sp³ | Pyramidal |
| Free Radical | Neutral | 7 (odd electron) | sp² | Planar |
| Carbene | Neutral | 6 (divalent) | sp² (singlet) or sp (triplet) | Bent or linear |
| Nitrene | Neutral | 6 (monovalent) | sp² (singlet) or sp (triplet) | Bent or linear |
| Benzyne | Neutral | 8 (in ring) | sp (in triple bond) | Linear |
| The structure and stability of each intermediate determines the course of the reaction. | ||||
Carbocations — The Positively Charged Intermediates
Definition: A carbocation is a positively charged carbon species with six electrons in its valence shell (sextet). It is sp² hybridised and planar in shape. The carbon bearing the positive charge is electron-deficient and acts as an electrophile.
Structure of Carbocations
- Hybridisation: sp²
- Geometry: Trigonal planar (bond angle 120°)
- Electron count: 6 electrons (sextet) — electron-deficient
- Empty p orbital: Perpendicular to the plane of the molecule
Stability of Carbocations — The Master Order
Stability Order: Benzyl ≈ Allyl > 3° > 2° > 1° > CH₃⁺
The stability of carbocations is determined by three factors:
- 1. Hyperconjugation: More α-hydrogens → more stabilisation. 3° carbocations have 9 α-H, 2° have 6, 1° have 3, and methyl has 0.
- 2. Inductive Effect: Alkyl groups are electron-donating (+I effect) and stabilise the positive charge.
- 3. Resonance: Benzyl and allyl carbocations are stabilised by resonance (delocalisation of the positive charge).
| Carbocation Type | Example | α-H Count | Stability |
|---|---|---|---|
| Methyl (CH₃⁺) | CH₃⁺ | 0 | Least stable |
| Primary (1°) | CH₃CH₂⁺ | 3 | Low |
| Secondary (2°) | (CH₃)₂CH⁺ | 6 | Moderate |
| Tertiary (3°) | (CH₃)₃C⁺ | 9 | High |
| Allylic | CH₂=CH-CH₂⁺ | — | Very high (resonance) |
| Benzylic | C₆H₅-CH₂⁺ | — | Very high (resonance) |
| The stability order is the single most important concept for carbocations in GOC-2 Reactive Intermediates & Mechanism. | |||
Carbocation Rearrangements
Carbocations undergo rearrangements (1,2-shifts) to form more stable carbocations. The driving force is the formation of a more stable intermediate.
- 1,2-Hydride Shift: A hydride (H⁻) moves from an adjacent carbon to the carbocation centre.
- 1,2-Alkyl Shift: An alkyl group moves from an adjacent carbon to the carbocation centre.
Important: Carbocation rearrangements are a common trap in JEE and NEET. Always check if a more stable carbocation can be formed by a 1,2-shift.
Carbanions — The Negatively Charged Intermediates
Definition: A carbanion is a negatively charged carbon species with eight electrons in its valence shell (octet). It is sp³ hybridised and pyramidal in shape. The carbon bearing the negative charge is electron-rich and acts as a nucleophile.
Structure of Carbanions
- Hybridisation: sp³ (generally) or sp² (when conjugated)
- Geometry: Pyramidal (trigonal pyramidal) or planar (when conjugated)
- Electron count: 8 electrons (octet) — electron-rich
- Lone pair: Occupies a hybrid orbital
Stability of Carbanions
Stability Order: Benzyl > Allyl > 1° > 2° > 3°
The stability of carbanions is the reverse of that of carbocations. This is because:
- 1. Inductive Effect: Alkyl groups are electron-donating (+I effect) and destabilise the negative charge.
- 2. Resonance: Benzyl and allyl carbanions are stabilised by resonance (delocalisation of the negative charge).
- 3. s-character: Higher s-character means more electronegative carbon, which stabilises the negative charge. sp > sp² > sp³.
| Carbanion Type | Example | Stability |
|---|---|---|
| Methyl (CH₃⁻) | CH₃⁻ | Lowest |
| Primary (1°) | CH₃CH₂⁻ | Low |
| Secondary (2°) | (CH₃)₂CH⁻ | Moderate |
| Tertiary (3°) | (CH₃)₃C⁻ | Highest (least stable among alkyl) |
| Allylic | CH₂=CH-CH₂⁻ | Very high (resonance) |
| Benzylic | C₆H₅-CH₂⁻ | Very high (resonance) |
| The stability order of carbanions is the reverse of carbocations. This is a key concept in GOC-2 Reactive Intermediates & Mechanism. | ||
Key Insight: Carbanions are stabilised by electron-withdrawing groups (−I or −M) and destabilised by electron-donating groups (+I or +M). This is the opposite of carbocations.
Free Radicals — The Neutral, Odd-Electron Intermediates
Definition: A free radical is a neutral carbon species with seven electrons in its valence shell (one unpaired electron). It is sp² hybridised and planar in shape. Free radicals are highly reactive due to the unpaired electron.
Structure of Free Radicals
- Hybridisation: sp²
- Geometry: Trigonal planar (bond angle 120°)
- Electron count: 7 electrons (one unpaired)
Stability of Free Radicals
Stability Order: Benzyl ≈ Allyl > 3° > 2° > 1° > CH₃•
The stability of free radicals follows the same order as carbocations because:
- 1. Hyperconjugation: More α-hydrogens → more stabilisation.
- 2. Inductive Effect: Alkyl groups are electron-donating (+I effect) and stabilise the unpaired electron.
- 3. Resonance: Benzyl and allyl radicals are stabilised by resonance.
Free Radical Reactions
Free radical reactions proceed through three steps:
- 1. Initiation: Formation of radicals from non-radical species (usually by heat or light).
- 2. Propagation: Radicals react with molecules to form new radicals (chain reaction).
- 3. Termination: Two radicals combine to form a non-radical product.
Important: Free radical halogenation is a classic example of a free radical reaction. The order of reactivity is F₂ > Cl₂ > Br₂ > I₂. Fluorination is explosive, and iodination is reversible.
Carbenes, Nitrenes, and Benzynes — The Advanced Intermediates
Carbenes (:CH₂)
Definition: A carbene is a neutral divalent carbon species with six electrons in its valence shell. It has two unshared electrons and is highly reactive.
- Types: Singlet carbene (electrons are paired) and Triplet carbene (electrons are unpaired).
- Singlet carbene: sp² hybridised, bent structure, electrophilic.
- Triplet carbene: sp hybridised, linear structure, biradical.
- Reactions: Addition to alkenes (cyclopropanation), insertion into C-H bonds.
Nitrenes (:NH)
Definition: A nitrene is a neutral monovalent nitrogen species with six electrons in its valence shell. It is the nitrogen analogue of a carbene.
- Types: Singlet nitrene (electrons are paired) and Triplet nitrene (electrons are unpaired).
- Reactions: Insertion into C-H bonds, addition to alkenes.
Benzynes (C₆H₄)
Definition: Benzyne (also called aryne) is a neutral, highly reactive species with a triple bond in a benzene ring. It is formed by elimination of two adjacent groups from a benzene ring.
- Structure: The triple bond is formed by sp² hybridised carbons, with the extra bond formed by sideways overlap of p orbitals.
- Reactions: Benzynes react with nucleophiles and undergo cycloaddition reactions.
- Formation: Benzyne is formed by elimination of HX from aryl halides (via benzyne mechanism).
Key Insight: Carbenes, nitrenes, and benzynes are highly reactive intermediates that are formed under specific conditions. They are less frequently tested but are important for advanced JEE and NEET questions.
Electrophiles and Nucleophiles — The Reactants
Definition: An electrophile is an electron-deficient species that seeks electrons (electron lover). A nucleophile is an electron-rich species that seeks positive centres (nucleus lover).
Electrophiles
- Definition: Accepts a pair of electrons to form a bond.
- Charge: Usually positively charged or neutral with an incomplete octet.
- Examples: H⁺, Cl⁺, Br⁺, NO₂⁺, SO₃, BF₃, AlCl₃, carbocations (R₃C⁺).
- Strength: Stronger electrophiles are more electron-deficient.
Nucleophiles
- Definition: Donates a pair of electrons to form a bond.
- Charge: Usually negatively charged or neutral with a lone pair.
- Examples: OH⁻, CN⁻, NH₃, H₂O, ROH, carbanions (R₃C⁻).
- Nucleophilicity: The ability of a species to donate electrons. It is related to basicity but not the same.
| Property | Electrophile | Nucleophile |
|---|---|---|
| Definition | Electron lover | Nucleus lover |
| Electron density | Electron-deficient | Electron-rich |
| Charge | Positive or neutral | Negative or neutral |
| Reacts with | Nucleophiles | Electrophiles |
| Examples | H⁺, BF₃, carbocations | OH⁻, NH₃, carbanions |
| The interaction between electrophiles and nucleophiles is the basis of all organic reactions. | ||
Important: Nucleophilicity is not the same as basicity. Nucleophilicity is a kinetic property (how fast a species attacks), while basicity is a thermodynamic property (equilibrium constant for protonation).
Leaving Groups — The Departing Species
Definition: A leaving group is a group that departs with a pair of electrons during a substitution or elimination reaction. Good leaving groups are weak bases.
Good Leaving Groups
Leaving Group Ability: I⁻ > Br⁻ > Cl⁻ > F⁻
The ability of a leaving group is determined by:
- Basicity: Weak bases are good leaving groups (conjugate acids have low pKa).
- Polarisability: Larger, more polarisable ions are better leaving groups.
| Leaving Group | Conjugate Acid | pKa | Leaving Group Ability |
|---|---|---|---|
| I⁻ | HI | -10 | Excellent |
| Br⁻ | HBr | -9 | Excellent |
| Cl⁻ | HCl | -7 | Good |
| F⁻ | HF | 3.2 | Poor |
| OH⁻ | H₂O | 15.7 | Very poor |
| OTs⁻ | TsOH | -2.8 | Excellent |
| The conjugate acid of a good leaving group has a low pKa (strong acid). | |||
Key Insight: The leaving group ability is directly related to the stability of the leaving group as an anion. Stable anions (weak bases) are good leaving groups.
Nucleophilic Substitution Reactions — SN1 and SN2
Definition: Nucleophilic substitution is a reaction in which a nucleophile replaces a leaving group from a carbon atom. The two main mechanisms are SN1 and SN2.
SN2 Mechanism — Bimolecular Nucleophilic Substitution
- One Step: Concerted reaction with backside attack.
- Kinetics: Rate = k[RX][Nu⁻] (second order).
- Stereochemistry: 100% inversion (Walden inversion).
- Substrate: CH₃X > 1° > 2° > 3° (steric hindrance).
- Solvent: Polar aprotic (e.g., acetone, DMSO, DMF).
- Nucleophile: Strong and concentrated.
- Leaving Group: Good leaving group required (I⁻ > Br⁻ > Cl⁻ > F⁻).
SN1 Mechanism — Unimolecular Nucleophilic Substitution
- Two Steps: C-X bond breaks first to form a carbocation intermediate, then nucleophile attacks.
- Kinetics: Rate = k[RX] (first order).
- Stereochemistry: Racemisation (50% retention + 50% inversion).
- Substrate: 3° > 2° > 1° > CH₃X (carbocation stability).
- Solvent: Polar protic (e.g., water, alcohol).
- Nucleophile: Weak is sufficient.
- Rearrangement: Possible via 1,2-shift.
- Leaving Group: Good leaving group required.
| Feature | SN1 | SN2 |
|---|---|---|
| Rate | k[RX] | k[RX][Nu⁻] |
| Steps | Two (C-X breaks first) | One (concerted) |
| Intermediate | Planar carbocation | None |
| Substrate | 3° > 2° > 1° | CH₃X > 1° > 2° > 3° |
| Stereochemistry | Racemisation | 100% inversion |
| Nucleophile | Weak is fine | Strong, concentrated |
| Solvent | Polar protic | Polar aprotic |
| Rearrangement | Possible | Never |
| Carbocation stability: Benzyl ≈ Allyl > 3° > 2° > 1°. | ||
Important: The choice between SN1 and SN2 depends on the substrate (1°, 2°, or 3°), the nucleophile (strong or weak), and the solvent (polar protic or polar aprotic). This is a frequently tested concept in GOC-2 Reactive Intermediates & Mechanism.
Elimination Reactions — E1 and E2
Definition: Elimination reactions are the removal of a halogen (X) and a hydrogen (H) from adjacent carbons to form a double bond. The two main mechanisms are E1 and E2.
E2 Mechanism — Bimolecular Elimination
- One Step: Concerted elimination with anti-periplanar β-H.
- Kinetics: Rate = k[RX][Base] (second order).
- Stereochemistry: Anti-periplanar (trans) elimination.
- Substrate: 3° > 2° > 1° (more substituted alkene).
- Base: Strong base (e.g., alc. KOH, t-BuOK).
- Solvent: Polar protic (e.g., alcohol).
E1 Mechanism — Unimolecular Elimination
- Two Steps: C-X bond breaks first to form a carbocation, then β-H is eliminated.
- Kinetics: Rate = k[RX] (first order).
- Stereochemistry: No strict requirement.
- Substrate: 3° > 2° > 1° (carbocation stability).
- Base: Weak base (e.g., water, alcohol).
- Solvent: Polar protic.
Saytzeff vs Hofmann
| Rule | Description | When followed |
|---|---|---|
| Saytzeff Rule | More substituted alkene (major product). | With strong bases (e.g., alc. KOH). |
| Hofmann Rule | Less substituted alkene (major product). | With bulky bases (e.g., t-BuOK). |
| Higher temperature always favours elimination over substitution. | ||
Key Insight: In 2-bromobutane, alc. KOH gives but-2-ene (Saytzeff) as the major product, and but-1-ene (Hofmann) as the minor product. With t-BuOK, the Hofmann product (but-1-ene) is major.
SN1 vs SN2 vs E1 vs E2 — The Complete Comparison
| Feature | SN1 | SN2 | E1 | E2 |
|---|---|---|---|---|
| Type | Substitution | Substitution | Elimination | Elimination |
| Molecularity | Unimolecular | Bimolecular | Unimolecular | Bimolecular |
| Rate | k[RX] | k[RX][Nu⁻] | k[RX] | k[RX][Base] |
| Steps | 2 | 1 | 2 | 1 |
| Intermediate | Carbocation | None | Carbocation | None |
| Substrate | 3° > 2° > 1° | 1° > 2° > 3° | 3° > 2° > 1° | 3° > 2° > 1° |
| Nucleophile/Base | Weak Nu | Strong Nu | Weak Base | Strong Base |
| Solvent | Polar protic | Polar aprotic | Polar protic | Polar protic |
| Stereochemistry | Racemisation | Inversion | — | Anti-periplanar |
| Rearrangement | Possible | No | Possible | No |
| Memorise this comparison table for GOC-2 Reactive Intermediates & Mechanism. It is frequently tested in JEE and NEET. | ||||
Golden Rule: To decide between SN1, SN2, E1, and E2, consider: (1) Substrate (1°, 2°, or 3°), (2) Nucleophile/Base (strong or weak), (3) Solvent (polar protic or polar aprotic), and (4) Temperature (higher favours elimination).
Practice Questions — From JEE and NEET
| Question | Answer |
|---|---|
| Q1: Arrange the following carbocations in decreasing order of stability: CH₃⁺, (CH₃)₂CH⁺, (CH₃)₃C⁺, C₆H₅CH₂⁺. | C₆H₅CH₂⁺ > (CH₃)₃C⁺ > (CH₃)₂CH⁺ > CH₃⁺ |
| Q2: Which is more stable: a primary carbanion or a tertiary carbanion? | Primary carbanion is more stable (reverse of carbocation stability). |
| Q3: What is the product of the reaction between 2-bromobutane and alc. KOH? | But-2-ene (Saytzeff product). |
| Q4: What is the product of the reaction between 2-bromobutane and t-BuOK? | But-1-ene (Hofmann product). |
| Q5: Which solvent favours SN2 reactions: acetone or water? | Acetone (polar aprotic) favours SN2. |
| Q6: Which solvent favours SN1 reactions: ethanol or DMSO? | Ethanol (polar protic) favours SN1. |
| Q7: What is the stereochemistry of an SN2 reaction? | 100% inversion (Walden inversion). |
| Q8: What is the stereochemistry of an SN1 reaction? | Racemisation (50% retention + 50% inversion). |
| Practise these types of questions to become comfortable with applying GOC-2 Reactive Intermediates & Mechanism concepts in exam scenarios. | |
All GOC-2 Formulas at a Glance
| Formula/Concept | What It Means |
|---|---|
| Carbocation Stability: Benzyl ≈ Allyl > 3° > 2° > 1° > CH₃⁺ | Stability order of carbocations |
| Carbanion Stability: Benzyl > Allyl > 1° > 2° > 3° | Stability order of carbanions (reverse of carbocations) |
| Free Radical Stability: Benzyl ≈ Allyl > 3° > 2° > 1° > CH₃• | Stability order of free radicals |
| Rate (SN2) = k[RX][Nu⁻] | SN2 kinetics (second order) |
| Rate (SN1) = k[RX] | SN1 kinetics (first order) |
| Rate (E2) = k[RX][Base] | E2 kinetics (second order) |
| Rate (E1) = k[RX] | E1 kinetics (first order) |
| Leaving Group Ability: I⁻ > Br⁻ > Cl⁻ > F⁻ | Order of leaving group ability |
| Memorise these formulas for GOC-2 Reactive Intermediates & Mechanism. They are the key to scoring full marks in this chapter. | |
Common Mistakes in GOC-2
- Confusing carbocation and carbanion stability: Carbocation stability: 3° > 2° > 1°. Carbanion stability: 1° > 2° > 3° (reverse).
- Misapplying SN1 vs SN2 conditions: SN1 is favoured by 3° halides and polar protic solvents; SN2 by 1° halides and polar aprotic solvents.
- Forgetting carbocation rearrangements: 1,2-shifts can occur to form more stable carbocations.
- Confusing SN1 and E1: Both share the same carbocation intermediate. The difference is in the nucleophile/base.
- Misapplying Saytzeff and Hofmann rules: Saytzeff gives the more substituted alkene; Hofmann gives the less substituted alkene with bulky bases.
- Forgetting that nucleophilicity ≠ basicity: Nucleophilicity is a kinetic property; basicity is a thermodynamic property.
Golden Rule: Always identify the substrate (1°, 2°, or 3°), the nucleophile/base (strong or weak), and the solvent (polar protic or polar aprotic). This systematic approach is the key to mastering GOC-2 Reactive Intermediates & Mechanism.
Why GOC-2 Matters for JEE and NEET
- High weightage: GOC-2 Reactive Intermediates & Mechanism appears in 2-3 questions in every JEE Main, JEE Advanced, and NEET chemistry paper.
- Foundation for organic chemistry: Understanding GOC-2 is essential for understanding reaction mechanisms, predicting products, and solving organic chemistry problems.
- Direct scoring: Many questions are direct, especially on carbocation stability, SN1 vs SN2, and Saytzeff vs Hofmann.
- Conceptual clarity: This chapter rewards students who understand the concepts rather than just memorizing formulas.
Why this guide helps: A comprehensive GOC-2 Reactive Intermediates & Mechanism guide with all concepts, definitions, tables, and practice questions saves you time during revision and helps you quickly recall everything during the exam. You won't need to look anywhere else.
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Frequently Asked Questions — GOC-2 Reactive Intermediates & Mechanism
What is GOC-2 in Organic Chemistry?
GOC-2 (General Organic Chemistry - Part 2) is the study of reactive intermediates and reaction mechanisms. It covers the formation, structure, stability, and reactions of carbocations, carbanions, free radicals, carbenes, nitrenes, and benzynes. It also includes the concepts of electrophiles and nucleophiles, and the mechanisms of substitution (SN1, SN2) and elimination (E1, E2) reactions.
What are the different types of reactive intermediates in organic chemistry?
The main reactive intermediates in organic chemistry are: Carbocations (positively charged carbon with 6 electrons), Carbanions (negatively charged carbon with 8 electrons), Free Radicals (neutral carbon with 7 electrons), Carbenes (neutral carbon with 6 electrons, divalent), Nitrenes (neutral nitrogen with 6 electrons, monovalent), and Benzynes (neutral, highly reactive, with a triple bond in a benzene ring).
What is the stability order of carbocations?
The stability order of carbocations is: Benzyl ≈ Allyl > 3° > 2° > 1° > CH₃⁺. This is due to the combined effects of hyperconjugation (more α-hydrogens in 3° > 2° > 1°) and resonance (benzyl and allyl are stabilised by resonance). Inductive effect also contributes to the stability of alkyl carbocations.
What is the difference between SN1 and SN2 reactions?
SN1 is a unimolecular nucleophilic substitution reaction that proceeds via a carbocation intermediate. It is favoured by tertiary halides, polar protic solvents, and weak nucleophiles. It results in racemisation. SN2 is a bimolecular nucleophilic substitution that occurs in one concerted step with backside attack. It is favoured by primary halides, polar aprotic solvents, and strong nucleophiles. It results in complete inversion of configuration (Walden inversion).
Can I download the GOC-2 Reactive Intermediates & Mechanism formula sheet PDF for free?
Yes. You can download the complete GOC-2 Reactive Intermediates & Mechanism formula sheet PDF for free using the download button on this page. It covers all reactive intermediates, electrophiles and nucleophiles, SN1, SN2, E1, E2 mechanisms, and reaction conditions in one comprehensive place for quick revision before JEE and NEET exams.
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