Cheat Sheet: Some Basic Principles & Techniques | Chemistry Class 11 - NEET PDF Download

 Page 1


Some Basic Principles & Techniques 
Introduction 
? Definition: Study of hydrocarbons and derivatives. 
? Carbon: Catenation, tetravalency (four bonds). 
Functional Groups & Homologous Series 
? Functional Group: Defines properties (e.g., -OH, -CHO). 
? Homologous Series: Differ by -CH
2
 (14 mass units). 
Classification 
? Open Chain: Alkanes (C-C), alkenes (C=C). 
? Closed Chain: Homocyclic (cyclopropane, benzene), heterocyclic (pyridine). 
Bond Fission 
? H o m o l y t i c: Free radicals, e.g., Cl
2
 ? 2 Cl•. 
? H e t e r o l y t i c: Ions, e.g., CH
3
Cl ? CH
3
? + Cl?. 
Electron Effects 
? Inductiv e: -I: -NO2 > -F; +I: -C(CH3)3 > -CH3. 
? Electr omeric: Temporary p-shift (±E). 
? Resonance: +R: -OH, -NH2; -R: -NO2, -CHO. 
? Hyper conjugation: s-p overlap, stabilizes carbocations. 
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Some Basic Principles & Techniques 
Introduction 
? Definition: Study of hydrocarbons and derivatives. 
? Carbon: Catenation, tetravalency (four bonds). 
Functional Groups & Homologous Series 
? Functional Group: Defines properties (e.g., -OH, -CHO). 
? Homologous Series: Differ by -CH
2
 (14 mass units). 
Classification 
? Open Chain: Alkanes (C-C), alkenes (C=C). 
? Closed Chain: Homocyclic (cyclopropane, benzene), heterocyclic (pyridine). 
Bond Fission 
? H o m o l y t i c: Free radicals, e.g., Cl
2
 ? 2 Cl•. 
? H e t e r o l y t i c: Ions, e.g., CH
3
Cl ? CH
3
? + Cl?. 
Electron Effects 
? Inductiv e: -I: -NO2 > -F; +I: -C(CH3)3 > -CH3. 
? Electr omeric: Temporary p-shift (±E). 
? Resonance: +R: -OH, -NH2; -R: -NO2, -CHO. 
? Hyper conjugation: s-p overlap, stabilizes carbocations. 
Isomerism 
? Structural: Chain, position, functional. 
? Stereoisomerism: Geometrical (cis-trans), optical (chiral C). 
Reaction Intermediates 
? Carbocation: R 3C ?, 3° > 2° > 1°. 
? Carbanion: R 3C ?, 1° > 2° > 3°. 
? Free Radical: R 3C•, 3° > 2° > 1°. 
? Carbene: :CH 2, electrophilic. 
IUPAC Nomenclature 
? Longest Chain: Includes functional group. 
? Lowest Number: For branching, functional groups. 
? Priority: -COOH > -SO 3H > -CHO > -OH. 
? Aromatic: Benzene, toluene. 
Reaction Types 
Substitution 
? CH4 + Cl2 ? CH3Cl + HCl (UV). 
? Mechanism: Initiation (Cl2 ? 2Cl•), propagation, termination. 
Addition 
? CH2=CH2 + Br2 ? CH2Br–CH2Br. 
? Mechanism: Br? forms bromonium ion, Br? adds. 
Page 3


Some Basic Principles & Techniques 
Introduction 
? Definition: Study of hydrocarbons and derivatives. 
? Carbon: Catenation, tetravalency (four bonds). 
Functional Groups & Homologous Series 
? Functional Group: Defines properties (e.g., -OH, -CHO). 
? Homologous Series: Differ by -CH
2
 (14 mass units). 
Classification 
? Open Chain: Alkanes (C-C), alkenes (C=C). 
? Closed Chain: Homocyclic (cyclopropane, benzene), heterocyclic (pyridine). 
Bond Fission 
? H o m o l y t i c: Free radicals, e.g., Cl
2
 ? 2 Cl•. 
? H e t e r o l y t i c: Ions, e.g., CH
3
Cl ? CH
3
? + Cl?. 
Electron Effects 
? Inductiv e: -I: -NO2 > -F; +I: -C(CH3)3 > -CH3. 
? Electr omeric: Temporary p-shift (±E). 
? Resonance: +R: -OH, -NH2; -R: -NO2, -CHO. 
? Hyper conjugation: s-p overlap, stabilizes carbocations. 
Isomerism 
? Structural: Chain, position, functional. 
? Stereoisomerism: Geometrical (cis-trans), optical (chiral C). 
Reaction Intermediates 
? Carbocation: R 3C ?, 3° > 2° > 1°. 
? Carbanion: R 3C ?, 1° > 2° > 3°. 
? Free Radical: R 3C•, 3° > 2° > 1°. 
? Carbene: :CH 2, electrophilic. 
IUPAC Nomenclature 
? Longest Chain: Includes functional group. 
? Lowest Number: For branching, functional groups. 
? Priority: -COOH > -SO 3H > -CHO > -OH. 
? Aromatic: Benzene, toluene. 
Reaction Types 
Substitution 
? CH4 + Cl2 ? CH3Cl + HCl (UV). 
? Mechanism: Initiation (Cl2 ? 2Cl•), propagation, termination. 
Addition 
? CH2=CH2 + Br2 ? CH2Br–CH2Br. 
? Mechanism: Br? forms bromonium ion, Br? adds. 
Elimination 
? CH3CH2Cl + KOH ? CH2=CH2 + HCl (alcoholic). 
? Mechanism: Base abstracts ß-H, Cl? leaves. 
Rearrangement 
? Pinacol ? Pinacolone (H2SO4). 
? Mechanism: Protonation, C migration. 
Mechanisms 
? Nucleophile: OH ?, CN ?. 
? Electrophile: H ?, Br ?. 
? Curved Arrows: Electron movement. 
Purification 
? Crystallization: Solubility-based. 
? Sublimation: Volatile solids. 
? Distillation: Simple, fractional, reduced pressure, steam. 
? Chromatography: Adsorption, partition. 
Qualitative Analysis 
? Nitrogen: Prussian blue (NaCN). 
? Sulphur: Violet (nitroprusside), PbS. 
? Halogens: AgNO 3 ppt (Cl: white, Br: pale yellow, I: yellow). 
? Phosphorus: Yellow ppt (molybdate). 
? N+S: Blood red ([Fe(SCN)]² ?). 
Page 4


Some Basic Principles & Techniques 
Introduction 
? Definition: Study of hydrocarbons and derivatives. 
? Carbon: Catenation, tetravalency (four bonds). 
Functional Groups & Homologous Series 
? Functional Group: Defines properties (e.g., -OH, -CHO). 
? Homologous Series: Differ by -CH
2
 (14 mass units). 
Classification 
? Open Chain: Alkanes (C-C), alkenes (C=C). 
? Closed Chain: Homocyclic (cyclopropane, benzene), heterocyclic (pyridine). 
Bond Fission 
? H o m o l y t i c: Free radicals, e.g., Cl
2
 ? 2 Cl•. 
? H e t e r o l y t i c: Ions, e.g., CH
3
Cl ? CH
3
? + Cl?. 
Electron Effects 
? Inductiv e: -I: -NO2 > -F; +I: -C(CH3)3 > -CH3. 
? Electr omeric: Temporary p-shift (±E). 
? Resonance: +R: -OH, -NH2; -R: -NO2, -CHO. 
? Hyper conjugation: s-p overlap, stabilizes carbocations. 
Isomerism 
? Structural: Chain, position, functional. 
? Stereoisomerism: Geometrical (cis-trans), optical (chiral C). 
Reaction Intermediates 
? Carbocation: R 3C ?, 3° > 2° > 1°. 
? Carbanion: R 3C ?, 1° > 2° > 3°. 
? Free Radical: R 3C•, 3° > 2° > 1°. 
? Carbene: :CH 2, electrophilic. 
IUPAC Nomenclature 
? Longest Chain: Includes functional group. 
? Lowest Number: For branching, functional groups. 
? Priority: -COOH > -SO 3H > -CHO > -OH. 
? Aromatic: Benzene, toluene. 
Reaction Types 
Substitution 
? CH4 + Cl2 ? CH3Cl + HCl (UV). 
? Mechanism: Initiation (Cl2 ? 2Cl•), propagation, termination. 
Addition 
? CH2=CH2 + Br2 ? CH2Br–CH2Br. 
? Mechanism: Br? forms bromonium ion, Br? adds. 
Elimination 
? CH3CH2Cl + KOH ? CH2=CH2 + HCl (alcoholic). 
? Mechanism: Base abstracts ß-H, Cl? leaves. 
Rearrangement 
? Pinacol ? Pinacolone (H2SO4). 
? Mechanism: Protonation, C migration. 
Mechanisms 
? Nucleophile: OH ?, CN ?. 
? Electrophile: H ?, Br ?. 
? Curved Arrows: Electron movement. 
Purification 
? Crystallization: Solubility-based. 
? Sublimation: Volatile solids. 
? Distillation: Simple, fractional, reduced pressure, steam. 
? Chromatography: Adsorption, partition. 
Qualitative Analysis 
? Nitrogen: Prussian blue (NaCN). 
? Sulphur: Violet (nitroprusside), PbS. 
? Halogens: AgNO 3 ppt (Cl: white, Br: pale yellow, I: yellow). 
? Phosphorus: Yellow ppt (molybdate). 
? N+S: Blood red ([Fe(SCN)]² ?). 
Quantitative Analysis 
? C, H: %C = (12/44) × (m_CO 2/m_sub) × 100. 
? Nitrogen: Dumas, Kjeldahl’s. 
? Halogens: %Cl = (35.5/143.5) × (m_AgCl/m_sub) × 100. 
? Sulphur: %S = (32/233) × (m_BaSO 4/m_sub) × 100. 
? Phosphorus: %P = (62/222) × (m_Mg 2P 2O 7/m_sub) × 100. 
? Oxygen: %O = (16/44) × (m_CO 2/m_sub) × 100. 
Problem-Solving Tactics 
? Name: Longest chain, lowest number, prioritize functional group. 
? Reactions: p-bond ? addition; leaving group ? substitution/elimination. 
? Effects: Use ±I, ±R for stability. 
? Purification: Solubility ? crystallization; volatility ? distillation. 
Reaction Table 
Type Reactants Reagent Products Notes 
Substitution 
Free Radical 
CH4 Cl2, UV CH3Cl + HCl 
Free radical 
mechanism