Alkynes

Alkynes | Class 11 Notes Acyclic unsaturated hydrocarbons containing a carbon-carbon triple bond are called alkynes or acetylenes. Their general formula is CnH2n-2 where n=2,3,4….etc.   Structure of Triple bond  Ethyne is the first member of alkynes series. Each carbon atom of ethyne is sp-hybridized and hence has two sp-hybridized orbitals. One sp-hybridized orbital of each…

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Alkenes

Alkenes | Class 11 Notes Acyclic unsaturated hydrocarbons containing a carbon-carbon double bond are called alkenes. They are also called olefins since the lower members of this class produce oily products on reaction with halogens such as chlorine and bromine. Structures of Double Bond The carbon-carbon double bond in alkenes consists of one strong carbon-carbon…

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Quantitative Analysis

Organic Chemistry | Some Basic Principles and Techniques | Chemistry | Class 11 Quantitative analysis means to determine the percentage of each element. Estimation of Carbon and Hydrogen Principle. A known mass of the organic compound is heated strongly with excess of dry copper oxide in a current of dry air or oxygen (free from carbon dioxide).…

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Alkanes

Alkanes | Hydrocarbons | Chemistry | Class 11 Hydrocarbons are divided into two types: 1) Acyclic or open chain hydrocarbons 2) Cyclic or closed chain hydrocarbons Acyclic or open chain hydrocarbons : These compounds contain open chains of carbon atom in their molecules. They are also called aliphatic hydrocarbons.These are further classified into following three…

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Qualitative Analysis

Qualitative analysis Qualitative analysis means to detect the various elements present in it.The elements which commonly occur in organic compounds are carbon, hydrogen, oxygen and nitrogen. Detection of Carbon and Hydrogen Principle: The presence of carbon and hydrogen, in an organic compound, is detected by heating the given compound with dry Copper(II) oxide or cupric oxide in a hard…

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Purification Of Organic Compounds

Some of the important methods which are commonly employed for the purification of organic compounds: (1) Filtration, 2) Crystallisation or Recrystallization, 3) Fractional crystallisation, 4) Sublimation, (5) Simple distillation, (6) Fractional distillation, (7) Distillation under reduced pressure (8) Steam distillation, (9) Differential extraction, and (10) Chromatography. Filtration The process of filtration is used to separate insoluble solid…

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Types of organic reactions

All the organic reactions can be classified into the following eight types: Substitution reactions Addition reactions Elimination reaction Rearrangement reactions Condensation reaction Isomerisation reaction Pericyclic reactions Polymerization reactions Substitution reaction A substitution reaction is that which involves the direct replacement of an atom or a group of atoms in an organic molecule by another atom…

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Free Radicals

A free radical may be defined as an atom or a group having an odd or unpaired electron.These are generally produced by homolytic cleavage of a covalent bond. Classification Free radicals are also classified as primary (1°) , secondary (2°) and tertiary (3°) according as the carbon carrying the unpaired electron is primary, secondary and…

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Carbanions

Chemical species bearing a negative charge on carbon and possessing eight electrons in its valence shell are called carbanions. These are produced by heterolytic cleavage of covalent bonds in which the shared pair of electrons remains with the carbon atom. Classification of carbanion Carbanions are also classified as primary (1°), secondary (2°) and tertiary (3°)…

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Carbocations

Most of the organic reactions occur through the involvement of certain chemical species.These are generally short lived and highly reactive and hence cannot be isolated.These short lived highly reactive chemical species through which the majority of the organic reactions occur are called reactive intermediates. Ex: Carbocation, carboanion, free radical, carbenes and nitrenes. Carbocation Chemical species…

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Hyperconjugation Effect

The inductive effect of the alkyl group on a saturated carbon chain follows the order: (CH3)3C > (CH3)2CH- > CH3CH2-> CH3– When an alkyl group is attached to an unsaturated system such as double bond or a benzene ring, the order of inductive effect is actually reversed.This effect is called hyperconjugation effect or Baker-Nathan effect.…

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Resonance or mesomerism

The phenomenon of resonance is said to occur whenever for a molecule we can write two or more Lewis structure which differ in the position of electrons but not in the relative position of atoms. The various Lewis structure, none of which is capable of describing all the known properties of the compound are called…

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Inductive and Electromeric Effect

Fission of a covalent bond Homolytic fission If a covalent bonds breaks in such a way that each atom takes away one electron of the shared pair, it is called homolytic or symmetrical fission. Homolytic fission is usually indicated by a fish arrow which denotes a one electron displacement. For Ex:  The neutral chemical species…

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Electrophiles and Nucleophiles

In an organic reaction, the organic compound called the substrate reacts with a suitable attacking species called the reagent to form products. The formation of products may occur either directly from the reactants through a transition state or through the formation of one or more intermediates. Sometimes by products are also formed from intermediates. Organic…

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Stereoisomerism

Isomers which have same structural formula but have different relative arrangement or atoms or groups in space are called stereoisomers and the phenomenon is called stereoisomerism. cis-trans isomerism is an example of stereoisomerism. Due to π-bonding between the two carbon atoms, the rotation around carbon-carbon double bond is prohibited and hence the geometry of the atoms…

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Structural Isomerism

Isomerism Two or more compounds having the same molecular formula but different chemical and physical properties are called isomers and the phenomenon is known as isomerism. It is of 2 types: 1) Structural isomerism 2) Stereoisomerism 1) Structural Isomerism : Compounds having the same molecular formula but different structures i.e. different arrangement of atoms within the…

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Nomenclature For Di and Polyfunctional Aromatic compounds

1) When an aromatic compound contains two or more functional group, it is named as a derivative of the compound with the principal functional group at position 1. 4-Nitrobenzoic acid 2-Aminophenol 3-Acetylbenzonitrile 4-Iodo-2-methylphenol 3-Bromo-4-hydroxybenzoic acid 2) If all the functional groups present in the benzene ring are such which are normally treated as substituent group,…

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Nomenclature of Simple aromatic compounds

Aromatic compounds contain one or more isolated or fused benzene rings.An aromatic compound consist of two parts : 1)Nucleus: The most ideal aromatic compound is benzene.It is represented by a regular hexagon of six carbon atoms with three alternate single and double bonds.This is called the nucleus.The ring may be represented by any of the following…

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