{"id":866661,"date":"2025-08-16T15:18:12","date_gmt":"2025-08-16T09:48:12","guid":{"rendered":"https:\/\/leverageedu.com\/discover\/?p=866661"},"modified":"2025-08-16T15:18:12","modified_gmt":"2025-08-16T09:48:12","slug":"ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf","status":"publish","type":"post","link":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/","title":{"rendered":"NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons (Free PDF)"},"content":{"rendered":"\n<p>Hydrocarbons are considered to be important compounds because they are used as fuels, lubricants, solvents, and as starting materials for the synthesis of many other useful compounds like plastics, fibres, drugs, explosives, dyes, etc. Below, we have provided important notes of NCERT Class 11 Chemistry (Part II), Chapter 9: Hydrocarbons, to help you understand the key concepts easily and prepare effectively for exams.<\/p>\n\n\n\n\n\n\n<p><strong>Explore Notes of Class 11 Chemistry<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background has-fixed-layout\" style=\"background-color:#ffbc8c\"><tbody><tr><td><strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-1-some-basic-concepts-of-chemistry\/\">Chapter 1<\/a><\/strong><\/td><td><strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-2-structure-of-atom\/\">Chapter 2<\/a><\/strong><\/td><td><strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-3-classification-of-elements-and-periodicity-in-properties\/\">Chapter 3<\/a><\/strong><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-class-11-chemistry-part-i-chapter-iv-chemical-bonding-and-molecular-structure\/\"><strong>Chapter 4<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-5-thermodynamics-free-pdf\/\"><strong>Chapter 5<\/strong><\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background has-fixed-layout\" style=\"background-color:#ddbff8\"><tbody><tr><td><a href=\"https:\/\/drive.google.com\/drive\/folders\/18Um1teL6_wF3S5idw0PnVxp-0yuDbTXE\"><strong>Download PDF of NCERT Notes Class 11 Chemistry (Part-II) Chapter-9: Hydrocarbons<\/strong><\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-introduction\">Introduction<\/h2>\n\n\n\n<p>Hydrocarbons are compounds containing only carbon and hydrogen atoms. It plays a major role in daily life as fuel, raw materials, and in manufacturing.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-common-fuels-and-sources\">Common Fuels and Sources<\/h3>\n\n\n\n<p>Common fuels and sources are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>LPG (Liquefied Petroleum Gas):<\/strong>\n<ul class=\"wp-block-list\">\n<li>Domestic fuel has the least pollution.<\/li>\n\n\n\n<li>Obtained from petroleum.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>CNG (Compressed Natural Gas):<\/strong>\n<ul class=\"wp-block-list\">\n<li>Formed by compressing natural gas.<\/li>\n\n\n\n<li>Used in automobiles, it causes less pollution.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>LNG (Liquified Natural Gas):<\/strong>\n<ul class=\"wp-block-list\">\n<li>Produced by the liquefaction of natural gas.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Petrol, Diesel, Kerosene Oil:<\/strong>\n<ul class=\"wp-block-list\">\n<li>Obtained by fractional distillation of petroleum from the earth\u2019s crust.<\/li>\n\n\n\n<li>Petrol and diesel are used in automobiles; petrol causes less pollution.<\/li>\n\n\n\n<li>Kerosene oil is used domestically, but it causes some pollution.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Coal Gas:<\/strong> Obtained by destructive distillation of coal.<\/li>\n\n\n\n<li><strong>Natural Gas:<\/strong> Found in upper strata during oil drilling.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-uses-of-hydrocarbons\">Uses of Hydrocarbons<\/h3>\n\n\n\n<p>The uses of hydrocarbons are<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>As fuels:<\/strong> LPG, CNG, LNG, petrol, diesel, kerosene, and coal gas.<\/li>\n\n\n\n<li><strong>Manufacturing of polymers:<\/strong> Polythene, polypropene, polystyrene, etc.<\/li>\n\n\n\n<li><strong>Solvents:<\/strong> Higher hydrocarbons are used as solvents for paints.<\/li>\n\n\n\n<li><strong>Chemical industry:<\/strong> Starting materials for dyes, drugs, and other organic compounds.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-classification-of-hydrocarbons\">Classification of Hydrocarbons<\/h2>\n\n\n\n<p>Hydrocarbons are classified into three main types based on the type of carbon\u2013carbon bonds:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Saturated Hydrocarbons<\/strong><strong><br><\/strong>\n<ul class=\"wp-block-list\">\n<li>Contain only single bonds (C\u2013C and C\u2013H).<\/li>\n\n\n\n<li><strong>Open chain:<\/strong> Alkanes (straight or branched).<\/li>\n\n\n\n<li><strong>Closed chain:<\/strong> Cycloalkanes.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Unsaturated Hydrocarbons<\/strong>\n<ul class=\"wp-block-list\">\n<li>Contain double bonds (alkenes), triple bonds (alkynes), or both.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Aromatic Hydrocarbons<\/strong>\n<ul class=\"wp-block-list\">\n<li>Special type of cyclic compounds, often with delocalised \u03c0-electrons (e.g., benzene).<\/li>\n\n\n\n<li>Can be homocyclic or heterocyclic.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<p class=\"has-pale-ocean-gradient-background has-background\"><strong>Also Read: <\/strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-psychology-chapter-1-what-is-psychology\/\"><strong>NCERT Notes Class 11 Psychology Chapter 1: What is Psychology? (Free PDF)<\/strong><\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-alkanes\">Alkanes<\/h2>\n\n\n\n<p>In this section, we have discussed the alkanes, along with their nomenclature, isomerism, preparation, and properties.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Saturated, open-chain hydrocarbons with C\u2013C single bonds.<\/li>\n\n\n\n<li>General formula: C\u2099H\u2082\u2099\u208a\u2082<\/li>\n\n\n\n<li>Example: Methane (CH\u2084), Ethane (C\u2082H\u2086), Propane (C\u2083H\u2088).<\/li>\n\n\n\n<li>Bonding: sp\u00b3 hybridised carbon atoms; tetrahedral geometry; bond angle = 109.5\u00b0; C\u2013C bond length = 154 pm; C\u2013H bond length = 112 pm.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-nomenclature-amp-isomerism\">Nomenclature &amp; Isomerism<\/h3>\n\n\n\n<p>The nomenclature and isomerism of alkanes are discussed below.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The first three alkanes (CH\u2084, C\u2082H\u2086, C\u2083H\u2088) have only one structure; higher alkanes exhibit <strong>structural isomerism<\/strong>.<\/li>\n\n\n\n<li><strong>Chain isomerism:<\/strong> Same molecular formula, different carbon chain arrangement.\n<ul class=\"wp-block-list\">\n<li>Example: C\u2084H\u2081\u2080 \u2192 n-butane &amp; isobutane.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Carbon atom classification:<\/strong>\n<ul class=\"wp-block-list\">\n<li>Primary (1\u00b0) \u2013 attached to 1 carbon.<\/li>\n\n\n\n<li>Secondary (2\u00b0) \u2013 attached to 2 carbons.<\/li>\n\n\n\n<li>Tertiary (3\u00b0) \u2013 attached to 3 carbons.<\/li>\n\n\n\n<li>Quaternary (4\u00b0) \u2013 attached to 4 carbons.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-preparation-of-alkanes\">Preparation of Alkanes<\/h3>\n\n\n\n<p>In this section, we have provided the key details relevant to the preparation of alkanes.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>From Unsaturated Hydrocarbons (Hydrogenation)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Alkene\/alkyne + H\u2082 \u2192 alkane<\/li>\n\n\n\n<li>Catalyst: Pt, Pd (room temp) or Ni (high temp\/pressure).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>From Alkyl Halides<\/strong>\n<ul class=\"wp-block-list\">\n<li>Reduction with Zn + dil. HCl \u2192 alkane.<\/li>\n\n\n\n<li><strong>Wurtz reaction:<\/strong> Alkyl halide + Na (dry ether) \u2192 higher alkane.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>From Carboxylic Acids<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Decarboxylation:<\/strong> Sodium salt of acid + soda lime \u2192 alkane (one C less).<\/li>\n\n\n\n<li><strong>Kolbe\u2019s electrolysis:<\/strong> Aqueous sodium salt of acid \u2192 alkane (even number of C atoms).<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-properties-of-alkanes\">Properties of Alkanes<\/h3>\n\n\n\n<p>The properties of alkanes are discussed below.<\/p>\n\n\n\n<p><strong>Physical:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Non-polar, insoluble in water, soluble in non-polar solvents.<\/li>\n\n\n\n<li>C\u2081\u2013C\u2084 \u2192 gases, C\u2085\u2013C\u2081\u2087 \u2192 liquids, \u2265 C\u2081\u2088 \u2192 solids.<\/li>\n\n\n\n<li>Boiling point \u2191 with molecular mass; branching \u2193 boiling point.<\/li>\n<\/ul>\n\n\n\n<p><strong>Chemical:<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Substitution Reactions<\/strong>\n<ul class=\"wp-block-list\">\n<li>Halogenation: CH\u2084 + Cl\u2082 \u2192 CH\u2083Cl \u2192 CH\u2082Cl\u2082 \u2192 CHCl\u2083 \u2192 CCl\u2084<\/li>\n\n\n\n<li>Mechanism: Free radical chain (initiation, propagation, termination).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Combustion<\/strong>\n<ul class=\"wp-block-list\">\n<li>Complete combustion \u2192 CO\u2082 + H\u2082O (high heat output, used as fuels).<\/li>\n\n\n\n<li>Incomplete combustion \u2192 carbon black.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Controlled Oxidation<\/strong>\n<ul class=\"wp-block-list\">\n<li>CH\u2084 + O\u2082 (Cu catalyst) \u2192 CH\u2083OH<\/li>\n\n\n\n<li>CH\u2084 + O\u2082 (Mo\u2082O\u2083 catalyst) \u2192 HCHO<\/li>\n\n\n\n<li>Tertiary alkanes oxidised by KMnO\u2084 \u2192 alcohol.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Isomerisation<\/strong>\n<ul class=\"wp-block-list\">\n<li>n-Alkane \u2192 branched alkane (AlCl\u2083 + HCl).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Aromatization (Reforming)<\/strong>\n<ul class=\"wp-block-list\">\n<li>n-Alkane (\u2265 C\u2086) \u2192 aromatic hydrocarbon (V\u2082O\u2085, MoO\u2083, Cr\u2082O\u2083 on Al\u2082O\u2083).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Reaction with Steam<\/strong>\n<ul class=\"wp-block-list\">\n<li>CH\u2084 + H\u2082O (Ni, 1273 K) \u2192 CO + H\u2082.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Pyrolysis (Cracking)<\/strong>\n<ul class=\"wp-block-list\">\n<li>High temp decomposition \u2192 lower alkanes + alkenes.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-conformations-of-alkanes\">Conformations of Alkanes<\/h2>\n\n\n\n<p>Conformations (also called conformers or rotamers) are different spatial arrangements of atoms in a molecule that can be interconverted by rotation around a single C\u2013C sigma bond without breaking any bonds. Due to the symmetrical electron distribution of \u03c3 bonds along the C\u2013C axis, alkanes allow such rotation.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Rotation &amp; Energy Barrier:<\/strong>\n<ul class=\"wp-block-list\">\n<li>Rotation is not completely free \u2013 hindered by torsional strain (1\u201320 kJ mol\u207b\u00b9) due to repulsion between electron clouds of adjacent bonds.<\/li>\n\n\n\n<li>Torsional strain = repulsive interaction between electron clouds in bonds on adjacent carbons.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Conformations of Ethane (C\u2082H\u2086):<\/strong>\n<ul class=\"wp-block-list\">\n<li>Contains one C\u2013C single bond, with each carbon bonded to three H atoms.<\/li>\n\n\n\n<li>Infinite conformations are possible by rotation, but two <strong>extreme cases<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Eclipsed Conformation:<\/strong>\n<ul class=\"wp-block-list\">\n<li>H atoms on one carbon are as close as possible to H atoms on the adjacent carbon.<\/li>\n\n\n\n<li>Maximum torsional strain \u2192 Higher energy \u2192 Less stable.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Staggered Conformation:<\/strong>\n<ul class=\"wp-block-list\">\n<li>H atoms are as far apart as possible.<\/li>\n\n\n\n<li>Minimum torsional strain \u2192 Lower energy \u2192 Most stable.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Skew Conformation:<\/strong>\n<ul class=\"wp-block-list\">\n<li>Any intermediate arrangement between staggered and eclipsed.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Representations of Conformations:<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Sawhorse Projection:<\/strong>\n<ul class=\"wp-block-list\">\n<li>C\u2013C bond drawn as a slanted line; front carbon shown at lower end, rear carbon at upper end; bonds drawn at 120\u00b0.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Newman Projection:<\/strong>\n<ul class=\"wp-block-list\">\n<li>View along C\u2013C axis; front carbon as a point, rear carbon as a circle; H atoms shown at 120\u00b0.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Relative Stability:<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Staggered<\/strong>: Minimum electron repulsion, lowest energy, most stable.<\/li>\n\n\n\n<li><strong>Eclipsed<\/strong>: Maximum electron repulsion, highest energy, least stable.<\/li>\n\n\n\n<li><strong>Energy difference<\/strong> \u2248 12.5 kJ mol\u207b\u00b9 (small enough for free rotation at room temperature).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p class=\"has-pale-ocean-gradient-background has-background\"><strong>Also Read: <\/strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-psychology-chapter-1-what-is-psychology\/\"><strong>NCERT Solutions Class 11 Psychology Chapter 1: What is Psychology? (Free PDF)<\/strong><\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-alkenes\">Alkenes<\/h2>\n\n\n\n<p>Alkenes are unsaturated hydrocarbons containing at least one C=C double bond. General formula: C\u2099H\u2082\u2099 (two hydrogen atoms less than alkanes). Also called olefins (\u201coil-forming\u201d) \u2013 e.g., ethylene (ethene, C\u2082H\u2084) forms oily liquids with Cl\u2082.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-structure-of-a-double-bond\">Structure of a Double Bond<\/h3>\n\n\n\n<p>The structure of a double bond is described below.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>C=C consists of:\n<ul class=\"wp-block-list\">\n<li>One \u03c3-bond: head-on overlap of sp\u00b2 hybrid orbitals (bond enthalpy \u2248 397 kJ mol\u207b\u00b9).<\/li>\n\n\n\n<li>One \u03c0-bond: lateral overlap of unhybridised p-orbitals (bond enthalpy \u2248 284 kJ mol\u207b\u00b9).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>Bond length: C=C (134 pm) &lt; C\u2013C (154 pm).<\/li>\n\n\n\n<li>\u03c0-bond is weaker \u2192 electrons are loosely held \u2192 site for electrophilic attack.<\/li>\n\n\n\n<li>Total bond strength: C=C (681 kJ mol\u207b\u00b9) > C\u2013C in ethane (348 kJ mol\u207b\u00b9).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-nomenclature-iupac\">Nomenclature (IUPAC)<\/h3>\n\n\n\n<p>The IUPAC Nomenclature of alkenes is provided below.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The longest chain containing C=C is chosen.<\/li>\n\n\n\n<li>Numbering starts from the end nearer to the double bond.<\/li>\n\n\n\n<li>Replace <strong>-ane<\/strong> with <strong>-ene<\/strong>.<\/li>\n\n\n\n<li>Examples:\n<ul class=\"wp-block-list\">\n<li>CH\u2083\u2013CH=CH\u2082 \u2192 <strong>Propene<\/strong><\/li>\n\n\n\n<li>CH\u2083\u2013CH\u2082\u2013CH=CH\u2082 \u2192 <strong>But-1-ene<\/strong><\/li>\n\n\n\n<li>CH\u2083\u2013CH=CH\u2013CH\u2083 \u2192 <strong>But-2-ene<\/strong><\/li>\n\n\n\n<li>CH\u2082=CH\u2013CH=CH\u2082 \u2192 <strong>Buta-1,3-diene<\/strong><\/li>\n\n\n\n<li>CH\u2082=C(CH\u2083)\u2082 \u2192 <strong>2-Methylprop-1-ene<\/strong><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-isomerism\">Isomerism<\/h3>\n\n\n\n<p>In this section, we have discussed the isomerism of alkenes.<\/p>\n\n\n\n<p>1. <strong>Structural Isomerism<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Chain &amp; position isomerism is possible from C\u2084H\u2088 onwards.<\/li>\n\n\n\n<li>Examples (C\u2084H\u2088): But-1-ene, But-2-ene, 2-Methylprop-1-ene.<\/li>\n<\/ul>\n\n\n\n<p>2. <strong>Geometrical (cis\u2013trans) Isomerism<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Due to <strong>restricted rotation<\/strong> around C=C.Cis<strong>s<\/strong>: identical groups on the same side of C=C.<\/li>\n\n\n\n<li><strong>Trans<\/strong>: identical groups on opposite sides.<\/li>\n\n\n\n<li>Example: cis- and trans-But-2-ene.<\/li>\n\n\n\n<li>cis form \u2192 more polar (e.g., \u03bc = 0.33 D), trans form \u2192 nearly non-polar.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-preparation\">Preparation<\/h3>\n\n\n\n<p>In this section, we have discussed the preparation of alkenes.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>From Alkynes<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Partial hydrogenation<\/strong> with Lindlar\u2019s catalyst \u2192 cis-alkene.<\/li>\n\n\n\n<li><strong>Reduction with Na \/ liquid NH\u2083<\/strong> \u2192 trans-alkene.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>From Alkyl Halides (Dehydrohalogenation)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Heat with alcoholic KOH \u2192 \u03b2-elimination \u2192 alkene.<\/li>\n\n\n\n<li>Rate: RI > RBr > RCl; tertiary > secondary > primary.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>From Vicinal Dihalides (Dehalogenation)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Treat with Zn \u2192 ZnX\u2082 eliminated \u2192 alkene.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>From Alcohols (Acidic Dehydration)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Heat with conc. H\u2082SO\u2084 \u2192 \u03b2-elimination \u2192 alkene.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-properties\">Properties<\/h3>\n\n\n\n<p>In this section, we have discussed the properties of alkenes,<\/p>\n\n\n\n<p><strong>Physical<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First 3 members: gases; next 14: liquids; last: solids.<\/li>\n\n\n\n<li>Insoluble in water; soluble in non-polar solvents.<\/li>\n\n\n\n<li>Boiling point \u2191 with chain length: straight-chain > branched.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"h-chemical-mainly-electrophilic-addition-reactions\"><strong>Chemical \u2013 Mainly Electrophilic Addition Reactions<\/strong><\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Addition of H\u2082<\/strong> \u2013 Ni, Pd, Pt catalysts \u2192 alkane.<\/li>\n\n\n\n<li><strong>Addition of Halogens<\/strong> \u2013 Br\u2082 \/ Cl\u2082 \u2192 vicinal dihalides; bromine water test for unsaturation.<\/li>\n\n\n\n<li><strong>Addition of HX<\/strong>\n<ul class=\"wp-block-list\">\n<li>Symmetrical alkenes \u2192 single product.<\/li>\n\n\n\n<li>Unsymmetrical alkenes \u2192 <strong>Markovnikov\u2019s Rule<\/strong> applies (negative part attaches to C with fewer H atoms).<\/li>\n\n\n\n<li><strong>Anti-Markovnikov (Peroxide effect)<\/strong> \u2013 only with HBr; free radical mechanism \u2192 opposite product.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Addition of H\u2082SO\u2084<\/strong> \u2013 Cold conc. H\u2082SO\u2084 \u2192 alkyl hydrogen sulfate \u2192 hydrolysis \u2192 alcohol (Markovnikov).<\/li>\n\n\n\n<li><strong>Hydration<\/strong> \u2013 H\u2082O + a few drops of conc. H\u2082SO\u2084 \u2192 alcohol (Markovnikov).<\/li>\n\n\n\n<li><strong>Oxidation<\/strong>\n<ul class=\"wp-block-list\">\n<li>Cold, dilute KMnO\u2084 (Baeyer\u2019s test) \u2192 vicinal glycols.<\/li>\n\n\n\n<li>Acidic KMnO\u2084 \/ K\u2082Cr\u2082O\u2087 \u2192 ketones\/acids.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Ozonolysis<\/strong> \u2013 O\u2083 addition + Zn\/H\u2082O cleavage \u2192 carbonyl compounds; locates C=C position.<\/li>\n\n\n\n<li><strong>PolYmerisation<\/strong> \u2013 High T, high P, catalyst \u2192 polythene, polypropene.<\/li>\n<\/ol>\n\n\n\n<p class=\"has-pale-ocean-gradient-background has-background\"><strong>Also Read: <\/strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-psychology-chapter-3-human-development\/\"><strong>NCERT Notes Class 11 Psychology Chapter 3: Human Development (Free PDF)<\/strong><\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-alkynes\">Alkynes<\/h2>\n\n\n\n<p>Alkynes are unsaturated hydrocarbons containing at least one C\u2261C triple bond. General formula: C\u2099H\u2082\u2099\u208b\u2082 (less hydrogen than alkenes or alkanes). First stable member: Ethyne (acetylene) \u2013 used in oxyacetylene welding. Serve as starting materials for various organic compounds.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-nomenclature-amp-isomerism-0\">Nomenclature &amp; Isomerism<\/h3>\n\n\n\n<p>The nomenclature and isomerism of alkynes are discussed below.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Common system<\/strong>: derivatives of acetylene.<\/li>\n\n\n\n<li><strong>IUPAC system<\/strong>: derivatives of alkanes with <strong>-yne<\/strong> suffix; position of triple bond indicated by the first triply bonded carbon.<\/li>\n\n\n\n<li><strong>Examples<\/strong>:\n<ul class=\"wp-block-list\">\n<li>HC\u2261CH \u2192 <strong>Ethyne<\/strong><\/li>\n\n\n\n<li>CH\u2083\u2013C\u2261CH \u2192 <strong>Propyne<\/strong><\/li>\n\n\n\n<li>CH\u2261C\u2013CH\u2082\u2013CH\u2083 \u2192 <strong>But-1-yne<\/strong><\/li>\n\n\n\n<li>CH\u2083\u2013C\u2261C\u2013CH\u2083 \u2192 <strong>But-2-yne<\/strong><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Isomerism<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Position isomerism<\/strong>: same chain, different location of triple bond (But-1-yne &amp; But-2-yne).<\/li>\n\n\n\n<li><strong>Chain isomerism<\/strong>: difference in carbon chain arrangement.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-structure-of-triple-bond\">Structure of Triple Bond<\/h3>\n\n\n\n<p>The structure of a triple bond is discussed below.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Example: Ethyne\n<ul class=\"wp-block-list\">\n<li>Each carbon: sp hybridised (linear geometry, 180\u00b0 bond angle).<\/li>\n\n\n\n<li>One \u03c3 bond (sp\u2013sp overlap) between C atoms, two \u03c3 bonds (sp\u20131s overlap) with H atoms.<\/li>\n\n\n\n<li>Two \u03c0 bonds from lateral overlap of unhybridised p orbitals.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>Bond details:\n<ul class=\"wp-block-list\">\n<li>C\u2261C bond enthalpy: 823 kJ mol\u207b\u00b9 (strongest).<\/li>\n\n\n\n<li>Bond lengths: C\u2261C (120 pm) &lt; C=C (133 pm) &lt; C\u2013C (154 pm).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>Molecule is linear; electron cloud cylindrically symmetrical.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-preparation-0\">Preparation<\/h3>\n\n\n\n<p>In this section, we have discussed the ways to prepare alkynes.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>From Calcium Carbide<\/strong>\n<ul class=\"wp-block-list\">\n<li>CaCO\u2083 \u2192 CaO \u2192 CaC\u2082 (with coke) \u2192 reacts with water \u2192 C\u2082H\u2082.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>From Vicinal Dihalides<\/strong>\n<ul class=\"wp-block-list\">\n<li>Alcoholic KOH \u2192 \u03b2-elimination \u2192 alkenyl halide \u2192 treated with NaNH\u2082 \u2192 alkyne.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-properties-0\">Properties<\/h3>\n\n\n\n<p>The physical and chemical properties of alkynes are discussed below.<\/p>\n\n\n\n<p><strong>Physical Properties<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First 3 members: gases; next 8: liquids; last: solids.<br><\/li>\n\n\n\n<li>Colourless (ethyne has a characteristic odour; others are odourless).<br><\/li>\n\n\n\n<li>Weakly polar; insoluble in water; soluble in organic solvents.<br><\/li>\n\n\n\n<li>Boiling\/melting points \u2191 with molar mass.<\/li>\n<\/ul>\n\n\n\n<p><strong>Chemical Properties<\/strong><\/p>\n\n\n\n<p><strong>A. Acidic Character<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Terminal alkynes (HC\u2261CH, CH\u2083\u2013C\u2261CH) have acidic H atoms attached to sp-hybridised carbons (50% s-character \u2192 higher electronegativity).<\/li>\n\n\n\n<li>React with <strong>Na<\/strong> or <strong>NaNH\u2082<\/strong> \u2192 sodium alkynides + H\u2082 gas.<\/li>\n\n\n\n<li>Acidity trend:<br>HC\u2261CH > H\u2082C=CH\u2082 > CH\u2083\u2013CH\u2083<br>HC\u2261CH > CH\u2083\u2013C\u2261CH >> CH\u2083\u2013C\u2261C\u2013CH\u2083.<\/li>\n\n\n\n<li>Test: distinguishes alkynes from alkenes &amp; alkanes.<\/li>\n<\/ul>\n\n\n\n<p><strong>Addition Reactions (Electrophilic Addition)<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Addition of H\u2082<\/strong>\n<ul class=\"wp-block-list\">\n<li>Catalyst: Ni\/Pd\/Pt.<\/li>\n\n\n\n<li>Stepwise: Alkyne \u2192 Alkene \u2192 Alkane.<\/li>\n\n\n\n<li>Lindlar\u2019s catalyst \u2192 cis-alkene; Na\/NH\u2083 \u2192 trans-alkene.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Addition of Halogens (X\u2082)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Decolourises Br\u2082 in CCl\u2084 (test for unsaturation).<\/li>\n\n\n\n<li>Yields di- or tetra-halo products.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Addition of Hydrogen Halides (HX)<\/strong>\n<ul class=\"wp-block-list\">\n<li>2 molecules add \u2192 geminal dihalides.<\/li>\n\n\n\n<li>Unsymmetrical alkynes follow <strong>Markovnikov\u2019s rule<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Addition of Water (Hydration)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Catalyst: HgSO\u2084 + dilute H\u2082SO\u2084, 333 K.<\/li>\n\n\n\n<li>Yields carbonyl compounds via enol-keto tautomerism.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<p><strong>Polymerisation<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Linear Polymerisation<\/strong>\n<ul class=\"wp-block-list\">\n<li>Forms <strong>polyacetylene<\/strong> (polyethyne) \u2013 a conductive polymer.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Cyclic Polymerisation<\/strong>\n<ul class=\"wp-block-list\">\n<li>3 ethyne molecules \u2192 benzene (at 873 K, red-hot Fe tube) \u2013 key aliphatic \u2192 aromatic conversion.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-aromatic-hydrocarbons\">Aromatic Hydrocarbons<\/h2>\n\n\n\n<p>Aromatic hydrocarbons, also known as arenes, are hydrocarbons in which the carbon atoms are arranged in one or more planar cyclic structures with a high degree of unsaturation. Most of these compounds have a pleasant smell (Greek word <em>aroma<\/em> = pleasant smelling), hence the term &#8220;aromatic compounds. The most common example is the benzene ring.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Classification<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Benzenoids<\/strong>: Aromatic compounds containing at least one benzene ring.<br><em>Examples<\/em>: Benzene, Toluene, Naphthalene, Biphenyl.<\/li>\n\n\n\n<li><strong>Non-benzenoids<\/strong>: Aromatic compounds without a benzene ring but containing another highly unsaturated ring with aromatic character.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-nomenclature-and-isomerism\">Nomenclature and Isomerism<\/h3>\n\n\n\n<p>All six hydrogen atoms in benzene are equivalent, so replacement of one hydrogen atom gives only one monosubstituted product.<\/p>\n\n\n\n<p><strong>Disubstitution<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Replacement of two hydrogen atoms can yield <strong>three position isomers<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Ortho (o)<\/strong>: Substituents at 1,2- or 1,6-positions.<\/li>\n\n\n\n<li><strong>Meta (m-)<\/strong>: Substituents at 1,3- or 1,5-positions.<\/li>\n\n\n\n<li><strong>Para (p-)<\/strong>: Substituents at 1,4-positions.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-structure-of-benzene\">Structure of Benzene<\/h3>\n\n\n\n<p><strong>Historical background of the Benzene structure<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Discovery<\/strong>: Michael Faraday (1825).<\/li>\n\n\n\n<li><strong>Formula<\/strong>: C\u2086H\u2086 \u2192 shows high unsaturation but unusually high stability.<\/li>\n\n\n\n<li><strong>Observation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Benzene forms a triozonide, indicating the presence of three double bonds.<\/li>\n\n\n\n<li>Produces only one ortho-disubstituted derivative, meaning all C\u2013C bonds and all hydrogen atoms are equivalent.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p><strong>Kekul\u00e9\u2019s Structure (1865)<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Proposed a cyclic hexagonal structure with alternating single and double bonds, each carbon bonded to one hydrogen atom.<\/li>\n\n\n\n<li>Problem: This structure predicts two distinct 1,2-dibromobenzenes (due to alternating single\/double bonds), but experimentally, only one is obtained.<\/li>\n<\/ul>\n\n\n\n<p><strong>Modification \u2013 Oscillation of Double Bonds<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Kekul\u00e9 suggested that double bonds oscillate between positions, making all C\u2013C bonds equivalent.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"h-resonance-and-stability\"><strong>Resonance and Stability<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Valence Bond Theory<\/strong>: Benzene is a resonance hybrid of two Kekul\u00e9 structures.<\/li>\n\n\n\n<li>Resonance structure is shown as a hexagon with a <strong>circle<\/strong> representing six delocalised \u03c0 electrons.<\/li>\n\n\n\n<li>All six carbon atoms are sp\u00b2 hybridised:\n<ul class=\"wp-block-list\">\n<li>Two sp\u00b2 orbitals form \u03c3 bonds with adjacent carbons.<\/li>\n\n\n\n<li>One sp\u00b2 orbital forms a \u03c3 bond with a hydrogen atom.<\/li>\n\n\n\n<li>The unhybridised p orbitals on each carbon atom overlap laterally to form a delocalised \u03c0 electron cloud above and below the ring.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p><strong>Bond length and planarity<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>X-ray diffraction: all C\u2013C bond lengths = 139 pm, intermediate between single bond (154 pm) and double bond (133 pm).<\/li>\n\n\n\n<li>Benzene is planar, and the delocalisation makes it more stable than a hypothetical cyclohexatriene.<\/li>\n\n\n\n<li>Delocalisation explains why benzene prefers substitution reactions rather than addition reactions.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-aromaticity\">Aromaticity<\/h3>\n\n\n\n<p>A compound is considered aromatic if it satisfies the following conditions (H\u00fcckel\u2019s Rule):<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>The molecule is planar.<\/li>\n\n\n\n<li>Complete delocalisation of \u03c0 electrons over the ring.<\/li>\n\n\n\n<li>The ring contains (4n + 2) \u03c0 electrons, where n = 0, 1, 2\u2026<\/li>\n<\/ol>\n\n\n\n<p><strong>Examples<\/strong>: Benzene, Pyridine, Furan, Naphthalene.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-preparation-of-benzene\">Preparation of Benzene<\/h3>\n\n\n\n<p>The benzene preparation is discussed below.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Cyclic Polymerisation of Ethyne<\/strong>\n<ul class=\"wp-block-list\">\n<li>At 873 K over red-hot iron:<br>3 C\u2082H\u2082 \u2192 C\u2086H\u2086<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Decarboxylation of Aromatic Acids<\/strong>\n<ul class=\"wp-block-list\">\n<li>Sodium benzoate + sodalime (NaOH + CaO, heat) \u2192 Benzene + Na\u2082CO\u2083.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Reduction of Phenol<\/strong>\n<ul class=\"wp-block-list\">\n<li>Phenol vapours passed over heated zinc dust:<br>C\u2086H\u2085OH + Zn \u2192 C\u2086H\u2086 + ZnO.<br><\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-properties-1\">Properties<\/h3>\n\n\n\n<p>Some of the physical and chemical properties are discussed below.<\/p>\n\n\n\n<p><strong>Physical Properties<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Non-polar molecules.<\/li>\n\n\n\n<li>Colourless liquids or solids with a characteristic aroma.<\/li>\n\n\n\n<li>Immiscible with water, miscible with organic solvents.<\/li>\n\n\n\n<li>Burn with sooty flame (due to high carbon content).<\/li>\n<\/ul>\n\n\n\n<p><strong>Chemical Properties<\/strong><\/p>\n\n\n\n<p><strong>(A) Electrophilic Substitution Reactions (SE)<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Nitration<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Reagents: Conc. HNO\u2083 + Conc. H\u2082SO\u2084 (nitrating mixture).<\/li>\n\n\n\n<li>Example: Benzene \u2192 Nitrobenzene.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Halogenation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Cl\u2082\/Br\u2082 in the presence of FeCl\u2083\/FeBr\u2083 \u2192 haloarenes.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Sulphonation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Heating benzene with fuming H\u2082SO\u2084 \u2192 benzene sulphonic acid.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Friedel\u2013Crafts Alkylation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Benzene + R\u2013X + AlCl\u2083 \u2192 alkylbenzene.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Friedel\u2013Crafts Acylation<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Benzene + RCOCl + AlCl\u2083 \u2192 acylbenzene.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<p><strong>Mechanism of Electrophilic Substitution:<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Generation of Electrophile (E\u207a)<\/strong> \u2013 e.g., NO\u2082\u207a in nitration, Cl\u207a in halogenation.<\/li>\n\n\n\n<li><strong>Formation of \u03c3-complex (arenium ion)<\/strong> \u2013 one C becomes sp\u00b3 hybridised.<\/li>\n\n\n\n<li><strong>Loss of Proton<\/strong> \u2013 aromaticity restored.<\/li>\n<\/ol>\n\n\n\n<p><strong>Addition Reactions<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Hydrogenation<\/strong> (Ni catalyst, high T\/P) \u2192 cyclohexane.<\/li>\n\n\n\n<li><strong>Chlorination<\/strong> under UV \u2192 benzene hexachloride (BHC).<\/li>\n<\/ul>\n\n\n\n<p><strong>Combustion<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Burns with sooty flame:<br>C\u2086H\u2086 + 15\/2 O\u2082 \u2192 6 CO\u2082 + 3 H\u2082O.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-directive-influence-of-substituents\">Directive Influence of Substituents<\/h3>\n\n\n\n<p><strong>Ortho\/Para Directing Groups<\/strong>: Activate the ring, increase electron density at o and p-positions.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Examples: \u2013OH, \u2013NH\u2082, \u2013OCH\u2083, \u2013CH\u2083, \u2013C\u2082H\u2085.<\/li>\n\n\n\n<li>Halogens: o\/p directing via resonance but overall deactivating via \u2013I effect.<\/li>\n<\/ul>\n\n\n\n<p><strong>Meta Directing Groups<\/strong>: Strongly electron-withdrawing, reducing electron density at o and p-positions.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Examples: \u2013NO\u2082, \u2013CN, \u2013CHO, \u2013COR, \u2013COOH, \u2013SO\u2083H.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-carcinogenicity-and-toxicity\">Carcinogenicity and Toxicity<\/h3>\n\n\n\n<p>Benzene and polynuclear aromatic hydrocarbons (PAHs) are toxic and carcinogenic. Examples: Anthracene, Benzo[a]pyrene. Formed during the incomplete combustion of tobacco, coal, and petroleum. It can enter the human body, damage DNA, and cause cancer.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-important-formulas-in-ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons\">Important Formulas in NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons<\/h2>\n\n\n\n<p>Here are the important formulas from NCERT Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Hydrocarbons<\/strong> \u2013 Compounds made up of only carbon and hydrogen atoms.<\/li>\n\n\n\n<li><strong>Alkanes<\/strong> \u2013 Saturated hydrocarbons containing only single covalent (\u03c3) bonds between carbon atoms with the general formula <strong>CnH\u2082n+\u2082<\/strong>.<\/li>\n\n\n\n<li><strong>Alkenes<\/strong> \u2013 Unsaturated hydrocarbons containing at least one double bond between carbon atoms with the general formula <strong>CnH\u2082n<\/strong>.<\/li>\n\n\n\n<li><strong>Alkynes<\/strong> \u2013 Unsaturated hydrocarbons containing at least one triple bond between carbon atoms with the general formula <strong>CnH\u2082n\u2013\u2082<\/strong>.<\/li>\n\n\n\n<li><strong>Aromatic Hydrocarbons (Arenes)<\/strong> \u2013 Hydrocarbons containing one or more benzene rings (benzenoids) or other highly unsaturated rings (non-benzenoids).<\/li>\n\n\n\n<li><strong>Conformations<\/strong> \u2013 Different spatial arrangements of atoms in a molecule that can be interconverted by rotation around a single bond.<\/li>\n\n\n\n<li><strong>Torsional Strain<\/strong> \u2013 Repulsive interaction between electron clouds of bonds on adjacent atoms, which hinders free rotation around C\u2013C single bond.<\/li>\n\n\n\n<li><strong>Isomerism in Hydrocarbons<\/strong> \u2013 Existence of two or more compounds with the same molecular formula but different structures (structural or conformational).<\/li>\n\n\n\n<li><strong>Resonance in Benzene<\/strong> \u2013 Delocalisation of \u03c0-electrons over the entire benzene ring, making all C\u2013C bonds equal in length and providing extra stability.<\/li>\n\n\n\n<li><strong>Aromaticity<\/strong> \u2013 Property of cyclic, planar, conjugated compounds to be unusually stable due to complete delocalisation of \u03c0-electrons following H\u00fcckel\u2019s rule (4n+2 \u03c0 electrons).<\/li>\n<\/ul>\n\n\n\n<p><strong>Explore Notes of Class 11 Chemistry<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background has-fixed-layout\" style=\"background-color:#ffbc8c\"><tbody><tr><td><strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-1-some-basic-concepts-of-chemistry\/\">Chapter 1<\/a><\/strong><\/td><td><strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-2-structure-of-atom\/\">Chapter 2<\/a><\/strong><\/td><td><strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-3-classification-of-elements-and-periodicity-in-properties\/\">Chapter 3<\/a><\/strong><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-class-11-chemistry-part-i-chapter-iv-chemical-bonding-and-molecular-structure\/\"><strong>Chapter 4<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-i-chapter-5-thermodynamics-free-pdf\/\"><strong>Chapter 5<\/strong><\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><strong>Download the Solutions of Other Chapters of Class 11 Chemistry<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background has-fixed-layout\" style=\"background-color:#ffe69f\"><tbody><tr><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-chemistry-part-1-chapter-1-some-basic-concepts-of-chemistry\/\"><strong>Chapter 1<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-chemistry-part-i-chapter-2-structure-of-atom-free-pdf\/\"><strong>Chapter 2<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-chemistry-part-1-chapter-3-classification-of-elements-and-periodicity-in-properties\/\"><strong>Chapter 3<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-chemistry-part-1-chapter-iv-chemical-bonding-molecular-structure\/\"><strong>Chapter 4<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-chemistry-part-i-chapter-6-equilibrium\/\"><strong>Chapter 5<\/strong><\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><strong>Related Reads<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table class=\"has-pale-ocean-gradient-background has-background has-fixed-layout\"><tbody><tr><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-english-woven-words-poem-1-the-peacock\/\"><strong>NCERT Notes Class 11 English Woven Words Poem 1: The Peacock (Free PDF)<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-english-woven-words-poem-1-the-peacock\/\"><strong>NCERT Solutions Class 11 English Woven Words Poem 1: The Peacock (Free PDF)<\/strong><\/a><\/td><\/tr><tr><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-english-woven-words-chapter-8-the-luncheon\/\"><strong>NCERT Notes Class 11 English Woven Words Chapter 8: The Luncheon (Free PDF)<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-solutions-class-11-english-woven-words-chapter-8-the-luncheon\/\"><strong>NCERT Solutions Class 11 English Woven Words Chapter 8: The Luncheon (Free PDF)<\/strong><\/a><\/td><\/tr><tr><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-sociology-chapter-1-sociology-and-society\/\"><strong>NCERT Class 11 Sociology Chapter 1 Sociology And Society Notes (Free PDF)<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-class-11-sociology-chapter-1-sociology-and-society-solutions-free-pdf\/\"><strong>NCERT Class 11 Sociology Chapter 1 Sociology and Society Solutions (Free PDF)<\/strong><\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Class 11th Chemistry | Classification of Hydrocarbons | Chapter 9: Hydrocarbons | NCERT\" width=\"1200\" height=\"675\" src=\"https:\/\/www.youtube.com\/embed\/or9HqTer9PQ?list=PLbOkUmjwMtHvh9Q21YR32zEpWa2UNKXs7\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p>Source- Ignited Minds<\/p>\n\n\n\n<p><strong>Explore notes on other subjects in the NCERT Class 11<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background has-fixed-layout\" style=\"background-color:#b1e2ff\"><tbody><tr><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-and-solutions-class-11-english\/\"><strong>English<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-and-solutions-class-11-sociology\/\"><strong>Sociology<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-and-solutions-class-11-geography\/\"><strong>Geography<\/strong><\/a><\/td><td><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-and-solutions-class-11-political-science\/\"><strong>Political Science<\/strong><\/a><\/td><td><strong><a href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-and-solutions-class-11-psychology\/\">Psychology<\/a><\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-faqs\">FAQs<\/h2>\n\n\n\n<div class=\"schema-faq wp-block-yoast-faq-block\"><div class=\"schema-faq-section\" id=\"faq-question-1755336353572\"><strong class=\"schema-faq-question\"><strong>Q1. Why are hydrocarbons considered important compounds?<\/strong><\/strong> <p class=\"schema-faq-answer\">Hydrocarbons are important because they are the primary sources of fuels (like LPG, CNG, petrol, diesel, and kerosene), raw materials for the manufacture of polymers, solvents, dyes, and drugs, and also serve as the basis of many organic compounds essential in daily life.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1755336422119\"><strong class=\"schema-faq-question\"><strong>Q2. Why is benzene exceptionally stable compared to other unsaturated hydrocarbons?<\/strong><\/strong> <p class=\"schema-faq-answer\">Benzene is exceptionally stable due to the delocalisation of six \u03c0 electrons over six carbon atoms, forming a resonance-stabilised structure. This equal distribution of electrons leads to uniform bond lengths (139 pm) and resistance towards addition reactions, making benzene more stable than hypothetical cyclohexatriene.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1755336437517\"><strong class=\"schema-faq-question\"><strong>Q3. Why is ethyne more acidic than ethene and ethane?<\/strong><\/strong> <p class=\"schema-faq-answer\">Ethyne is more acidic because the hydrogen atoms are attached to sp-hybridised carbon atoms, which have the highest s-character (50%). This increases the electronegativity of carbon, pulling electron density towards itself and making the C\u2013H bond weaker. As a result, ethyne can release protons more easily than ethene (sp\u00b2) and ethane (sp\u00b3).<\/p> <\/div> <\/div>\n\n\n\n<p>For more topics, follow LeverageEdu <a href=\"https:\/\/leverageedu.com\/discover\/category\/school-education\/ncert-study-material\/\"><strong>NCERT Study Material<\/strong><\/a> today!&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"Hydrocarbons are considered to be important compounds because they are used as fuels, lubricants, solvents, and as starting&hellip;\n","protected":false},"author":133,"featured_media":866670,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"editor_notices":[],"footnotes":""},"categories":[477,389],"tags":[],"class_list":{"0":"post-866661","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-ncert-study-material","8":"category-school-education"},"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.3 (Yoast SEO v27.3) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons (Free PDF) - Leverage Edu Discover<\/title>\n<meta name=\"description\" content=\"Download free NCERT Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons notes in PDF format. Covers basic principles, techniques, formulas, classifications, and reactions\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons (Free PDF)\" \/>\n<meta property=\"og:description\" content=\"Download free NCERT Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons notes in PDF format. Covers basic principles, techniques, formulas, classifications, and reactions\" \/>\n<meta property=\"og:url\" content=\"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/\" \/>\n<meta property=\"og:site_name\" content=\"Leverage Edu Discover\" \/>\n<meta property=\"article:published_time\" content=\"2025-08-16T09:48:12+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/9\/2025\/08\/21083916\/NCERT-Notes-Class-11-Chemistry-Part-II-Chapter-9-Hydrocarbons-Free-PDF.webp\" \/>\n\t<meta property=\"og:image:width\" content=\"1024\" \/>\n\t<meta property=\"og:image:height\" content=\"640\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/webp\" \/>\n<meta name=\"author\" content=\"Devanshu Srivastava\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Devanshu Srivastava\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"15 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons (Free PDF) - Leverage Edu Discover","description":"Download free NCERT Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons notes in PDF format. Covers basic principles, techniques, formulas, classifications, and reactions","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/","og_locale":"en_US","og_type":"article","og_title":"NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons (Free PDF)","og_description":"Download free NCERT Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons notes in PDF format. Covers basic principles, techniques, formulas, classifications, and reactions","og_url":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/","og_site_name":"Leverage Edu Discover","article_published_time":"2025-08-16T09:48:12+00:00","og_image":[{"width":1024,"height":640,"url":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/9\/2025\/08\/21083916\/NCERT-Notes-Class-11-Chemistry-Part-II-Chapter-9-Hydrocarbons-Free-PDF.webp","type":"image\/webp"}],"author":"Devanshu Srivastava","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Devanshu Srivastava","Est. reading time":"15 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#article","isPartOf":{"@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/"},"author":{"name":"Devanshu Srivastava","@id":"https:\/\/leverageedu.com\/discover\/#\/schema\/person\/4100048e2da2b688952b61b843288395"},"headline":"NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons (Free PDF)","datePublished":"2025-08-16T09:48:12+00:00","mainEntityOfPage":{"@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/"},"wordCount":3050,"commentCount":0,"image":{"@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#primaryimage"},"thumbnailUrl":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/9\/2025\/08\/21083916\/NCERT-Notes-Class-11-Chemistry-Part-II-Chapter-9-Hydrocarbons-Free-PDF.webp","articleSection":["NCERT Study Material","School Education"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#respond"]}]},{"@type":["WebPage","FAQPage"],"@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/","url":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/","name":"NCERT Notes Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons (Free PDF) - Leverage Edu Discover","isPartOf":{"@id":"https:\/\/leverageedu.com\/discover\/#website"},"primaryImageOfPage":{"@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#primaryimage"},"image":{"@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#primaryimage"},"thumbnailUrl":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/9\/2025\/08\/21083916\/NCERT-Notes-Class-11-Chemistry-Part-II-Chapter-9-Hydrocarbons-Free-PDF.webp","datePublished":"2025-08-16T09:48:12+00:00","author":{"@id":"https:\/\/leverageedu.com\/discover\/#\/schema\/person\/4100048e2da2b688952b61b843288395"},"description":"Download free NCERT Class 11 Chemistry (Part-II) Chapter 9: Hydrocarbons notes in PDF format. 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His expertise lies in simplifying complex information into engaging, student-friendly content. Passionate about global education, Devanshu crafts stories that empower students to make informed decisions about their academic and career journeys.","sameAs":["https:\/\/www.linkedin.com\/in\/devsrivastava3"],"url":"https:\/\/leverageedu.com\/discover\/author\/devanshusrivastava\/"},{"@type":"Question","@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#faq-question-1755336353572","position":1,"url":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#faq-question-1755336353572","name":"Q1. Why are hydrocarbons considered important compounds?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Hydrocarbons are important because they are the primary sources of fuels (like LPG, CNG, petrol, diesel, and kerosene), raw materials for the manufacture of polymers, solvents, dyes, and drugs, and also serve as the basis of many organic compounds essential in daily life.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#faq-question-1755336422119","position":2,"url":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#faq-question-1755336422119","name":"Q2. Why is benzene exceptionally stable compared to other unsaturated hydrocarbons?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Benzene is exceptionally stable due to the delocalisation of six \u03c0 electrons over six carbon atoms, forming a resonance-stabilised structure. This equal distribution of electrons leads to uniform bond lengths (139 pm) and resistance towards addition reactions, making benzene more stable than hypothetical cyclohexatriene.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#faq-question-1755336437517","position":3,"url":"https:\/\/leverageedu.com\/discover\/school-education\/ncert-notes-class-11-chemistry-part-ii-chapter-9-hydrocarbons-free-pdf\/#faq-question-1755336437517","name":"Q3. Why is ethyne more acidic than ethene and ethane?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Ethyne is more acidic because the hydrogen atoms are attached to sp-hybridised carbon atoms, which have the highest s-character (50%). This increases the electronegativity of carbon, pulling electron density towards itself and making the C\u2013H bond weaker. As a result, ethyne can release protons more easily than ethene (sp\u00b2) and ethane (sp\u00b3).","inLanguage":"en-US"},"inLanguage":"en-US"}]}},"acf":[],"_links":{"self":[{"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/posts\/866661","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/users\/133"}],"replies":[{"embeddable":true,"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/comments?post=866661"}],"version-history":[{"count":0,"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/posts\/866661\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/media\/866670"}],"wp:attachment":[{"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/media?parent=866661"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/categories?post=866661"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/leverageedu.com\/discover\/wp-json\/wp\/v2\/tags?post=866661"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}