# Class 11 Chemistry Unit 8 Notes | SwaVid NCERT Class 11 Chemistry notes: key ideas, formulas, common mistakes and 3 quick checks with worked answers, written by SwaVid from the NCERT textbook. Canonical: https://www.swavid.com/cbse/class-11/chemistry/chapter/organic-chemistry-some-basic-principles-and-techniques Source: https://www.swavid.com/cbse/class-11/chemistry/chapter/organic-chemistry-some-basic-principles-and-techniques # Organic Chemistry - Some Basic Principles and Techniques ## Formulas and definitions ## Key ideas ## Common mistakes ## Quick checks ## Keep going ## Questions parents ask ## Class 11 Chemistry on SwaVid ### Tetravalence and shapes of carbon compounds ### Structural representations and classification ### IUPAC nomenclature and isomerism ### Fundamental concepts in organic reactions ### Electronic displacements in covalent bonds ### Purification methods ### Qualitative and quantitative analysis ### Next chapter ### Related chapter ### Related chapter ### All chapters SwaVid › CBSE › Class 11 › Chemistry › Organic Chemistry - Some Basic Principles and Techniques Notes written by SwaVid from the NCERT textbook. Class 11 Chemistry, Unit 8. Key ideas, formulas and common mistakes. CBSE prints 11 marks for Unit 8, not for this chapter alone. Short answer. This chapter introduces the fundamental concepts of organic chemistry, including tetravalence of carbon, hybridization, IUPAC nomenclature, isomerism, and reaction mechanisms. It also details the experimental techniques used for the purification, qualitative detection, and quantitative estimation of elements in organic compounds. Source: NCERT Chemistry Part II (Reprint 2026-27) , Unit 8, Organic Chemistry - Some Basic Principles and Techniques Carbon forms single, double, or triple bonds using sp³, sp², or sp hybridization, which lead to tetrahedral, planar, and linear geometries respectively. The presence of pi bonds influences the bond lengths, bond enthalpies, and planar arrangements of the atoms. Organic molecules can be represented using complete, condensed, or bond-line structural formulas, and three-dimensional wedge-and-dash projections. They are broadly classified into acyclic (open chain) and cyclic (homocyclic, heterocyclic, alicyclic, and aromatic) systems. Systematic naming follows the format of prefix, root word, primary suffix, and secondary suffix based on the principal functional group. Isomerism is divided into structural isomerism (chain, position, functional group, and metamerism) and stereoisomerism (geometrical and optical). Covalent bonds undergo homolytic fission to generate neutral free radicals or heterolytic fission to form carbocations and carbanions. Attacking reagents act as electrophiles (electron-deficient) or nucleophiles (electron-rich). Electron displacement occurs permanently through inductive, resonance, and hyperconjugation effects, or temporarily via the electromeric effect during a reaction. Hyperconjugation involves the delocalization of sigma electrons of a C-H bond with an adjacent empty p orbital or pi system. Common purification techniques include sublimation, crystallization, simple distillation, fractional distillation, steam distillation, and differential solvent extraction. Chromatography separates components based on differential distribution between a stationary phase and a mobile phase. Lassaigne's test detects nitrogen, sulfur, and halogens by fusing the organic compound with sodium metal to form ionic sodium salts. Quantitative methods such as the Liebig method (C and H), Dumas and Kjeldahl methods (N), and the Carius method (halogens and S) estimate elemental percentages. Try each question first. Then tap it to see the answer. Atomic mass of S = 32 g mol⁻¹ and molar mass of BaSO₄ = 233 g mol⁻¹ Mass of sulfur = (32 / 233) × 0.668 g = 0.09174 g % S = (0.09174 / 0.468) × 100 = 19.60% 19.60% Pressure of dry N₂ gas, P₁ = 715 - 15 = 700 mm Hg Use (P₁ × V₁) / T₁ = (P₀ × V₀) / T₀ V₀ = (700 × 50 × 273) / (760 × 300) = 9555000 / 228000 = 41.9 mL 41.9 mL Rf = (distance moved by compound) / (distance moved by solvent front) Rf = 4.2 / 7.0 = 0.60 0.60 Hydrocarbons . Chemical Bonding and Molecular Structure . Some Basic Concepts of Chemistry . The 9 chapters of Class 11 Chemistry . CBSE does not give marks to one chapter. It prints 11 marks for Unit 8, Organic Chemistry: Some basic Principles and Techniques, which includes Organic Chemistry - Some Basic Principles and Techniques. No. They are written by SwaVid from the NCERT textbook. The CBSE curriculum is the reference for what is assessed. Hydrocarbons. SwaVid is an AI tutor for Indian students in Classes 6 to 12. It finds the earlier ideas a child missed, then teaches today’s chapter. Start free to see how it works. - Unit 8 NCERT book - 11 marks, Unit 8 - 3 quick checks - Assigning lowest numbers to double or triple bonds instead of the principal functional group . Always identify the principal functional group first, as it receives the lowest numbering priority over carbon-carbon multiple bonds and substituents. - Applying Kjeldahl's method to nitro compounds, azo compounds, or pyridine . Do not use Kjeldahl's method for compounds containing nitrogen in a nitro group, azo group, or in a ring because their nitrogen does not convert into ammonium sulfate under these conditions. - Confusing inductive effect with electromeric effect . Remember that the inductive effect is a permanent shift along sigma bonds, whereas the electromeric effect is a temporary complete transfer of pi electrons that occurs only in the presence of an attacking reagent. - Using simple distillation to separate liquids with very close boiling points . Use fractional distillation when the difference in boiling points between two miscible liquids is small. ## Key Links - [CBSE](https://www.swavid.com/cbse) - [Class 11](https://www.swavid.com/cbse/class-11) - [Chemistry](https://www.swavid.com/cbse/class-11/chemistry/chapters) - [Start free →](https://www.swavid.com/signup) - [All 9 chapters](https://www.swavid.com/cbse/class-11/chemistry/chapters) - [NCERT Chemistry Part II (Reprint 2026-27)](https://ncert.nic.in/textbook.php) - [Open notes](https://www.swavid.com/cbse/class-11/chemistry/chapter/hydrocarbons) - [Open notes](https://www.swavid.com/cbse/class-11/chemistry/chapter/chemical-bonding-and-molecular-structure) - [Open notes](https://www.swavid.com/cbse/class-11/chemistry/chapter/some-basic-concepts-of-chemistry) - [Class 11 Chemistry](https://www.swavid.com/cbse/class-11/chemistry/chapters) - [Start free →](https://www.swavid.com/signup)