1. Carbon Bonds

Carbon bonds are fundamental to organic chemistry, forming the backbone of organic molecules. Carbon atoms can form single, double, or triple bonds with other carbon atoms or with other elements, such as hydrogen, oxygen, nitrogen, and halogens. The ability of carbon to form four covalent bonds and create various chains and rings is the basis for the vast diversity of organic compounds.

Examples

• Single Bond: Methane (CH4) – Each carbon atom forms four single bonds with hydrogen atoms.
• Double Bond: Ethene (C2H4) – Each carbon atom forms one double bond with another carbon atom and two single bonds with hydrogen atoms.
• Triple Bond: Ethyne (C2H2) – Each carbon atom forms one triple bond with another carbon atom and one single bond with a hydrogen atom.

Carbon atoms can form strong covalent bonds with each other, creating long chains (alkanes), branched chains, and ring structures (cycloalkanes). The versatility in bonding allows for a wide variety of structural configurations and functional groups, making organic chemistry a diverse and complex field of study.

Tip for Easy Remembering

Remember the mnemonic “CHT” (Carbon, Hydrogen, Triple) to recall that carbon can form single, double, and triple bonds, significantly impacting the structure and reactivity of organic compounds.

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2. Structure of Compound

The structure of a compound refers to the spatial arrangement of atoms within a molecule. Understanding the structure is crucial as it determines the physical and chemical properties of the compound. Organic compounds can be linear, branched, or cyclic, with varying degrees of complexity.

Examples

• Linear Structure: n-Butane (C4H10) – A straight-chain alkane with four carbon atoms.
• Branched Structure: Isobutane (C4H10) – A branched-chain alkane with a central carbon atom bonded to three other carbons.
• Cyclic Structure: Cyclohexane (C6H12) – A ring structure with six carbon atoms.

The structural formula of a compound provides a graphical representation of the molecule, showing the connectivity between atoms. Structural isomers have the same molecular formula but different arrangements of atoms, leading to distinct properties. Stereochemistry, which includes the study of spatial arrangement and orientation of atoms, is also an important aspect of the structure.

Tip for Easy Remembering

To remember different structures, think of “BLC” (Branched, Linear, Cyclic). Visualize each structure as different shapes – a straight line for linear, a branch for branched, and a circle for cyclic.

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3. Molecular Formula

The molecular formula of an organic compound represents the number and types of atoms present in a molecule. It provides the simplest representation of the compound, indicating the actual number of each type of atom.

Examples

• Methane: CH4 – Contains one carbon atom and four hydrogen atoms.
• Ethane: C2H6 – Contains two carbon atoms and six hydrogen atoms.
• Glucose: C6H12O6 – Contains six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.

The molecular formula does not convey information about the structure or arrangement of atoms. For instance, both n-butane and isobutane share the same molecular formula (C4H10) but have different structures. Empirical formulas represent the simplest whole-number ratio of atoms, while molecular formulas provide the actual numbers.

Tip for Easy Remembering

Use the acronym “MAC” (Molecular formula, Actual count, Composition) to remember that the molecular formula provides the actual count of each type of atom in the compound.

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4. Alkaline Category

The alkaline category, also known as alkanes, consists of saturated hydrocarbons with single bonds between carbon atoms. Alkanes follow the general formula CnH2n+2, where “n” is the number of carbon atoms. They are the simplest type of hydrocarbons and are also called paraffins.

Examples

• Methane: CH4 – The simplest alkane.
• Ethane: C2H6 – A two-carbon alkane.
• Propane: C3H8 – A three-carbon alkane.

Alkanes are relatively unreactive compared to other hydrocarbons due to the strong C-C and C-H bonds. They undergo combustion reactions, producing carbon dioxide and water, and can also participate in substitution reactions with halogens. Alkanes are found in natural gas and petroleum and are used as fuels and lubricants.

Tip for Easy Remembering

Remember “SAH” (Single bonds, Alkanes, Hydrocarbons) to recall that alkanes are saturated hydrocarbons with single bonds.

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5. Saturated Hydrocarbons

Saturated hydrocarbons are compounds that consist entirely of single bonds between carbon atoms and contain the maximum number of hydrogen atoms. These compounds are also known as alkanes. They have a general formula of CnH2n+2 and are characterized by their lack of double or triple bonds.

Examples

• Methane (CH4): The simplest saturated hydrocarbon.
• Ethane (C2H6): A two-carbon saturated hydrocarbon.
• Propane (C3H8): A three-carbon saturated hydrocarbon.

Saturated hydrocarbons are generally less reactive than unsaturated hydrocarbons because they lack the reactivity associated with double or triple bonds. They primarily undergo combustion and substitution reactions. Saturated hydrocarbons are used as fuels (e.g., methane in natural gas, propane in portable stoves) and as solvents.

Tip for Easy Remembering

Use the mnemonic “SHS” (Saturated Hydrocarbons, Single bonds) to remember that saturated hydrocarbons only have single bonds between carbon atoms.

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6. IUPAC Nomenclature

The International Union of Pure and Applied Chemistry (IUPAC) nomenclature system is a standardized method for naming organic compounds. This system ensures that each compound has a unique and systematic name that conveys its structure and composition.

Examples

• Methane (CH4): The simplest alkane, named by combining the prefix “meth-” (one carbon) with the suffix “-ane” (alkane).
• Ethanol (CH3CH2OH): Named by combining the prefix “eth-” (two carbons) with the suffix “-anol” (alcohol).
• 2-Methylpropane (CH3CH(CH3)CH3): Named by identifying the longest carbon chain (propane) and indicating the methyl group attached to the second carbon.

The IUPAC nomenclature involves several steps:

1. Identify the longest carbon chain.
2. Number the carbon atoms in the chain, starting from the end closest to a substituent.
3. Name the substituents and assign their position numbers.
4. Combine the substituents’ names and positions with the base name of the compound.

Tip for Easy Remembering

Remember the acronym “ILNC” (Identify, Longest chain, Numbering, Combine) to recall the steps of IUPAC nomenclature.

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7. Organic Compounds

Organic compounds are chemical compounds primarily composed of carbon and hydrogen, often with additional elements such as oxygen, nitrogen, sulfur, and halogens. They form the basis of all living organisms and many synthetic materials.

Examples

• Methane (CH4): The simplest organic compound.
• Glucose (C6H12O6): A fundamental sugar in biology.
• Ethanol (C2H5OH): A common alcohol used in beverages and as a solvent.

Organic compounds are classified based on their functional groups and structure. Major classes include hydrocarbons (alkanes, alkenes, alkynes), alcohols, aldehydes, ketones, carboxylic acids, and esters. Organic chemistry studies the structure, properties, reactions, and synthesis of these compounds.

Tip for Easy Remembering

Think of “CHONS” (Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur) to recall the common elements found in organic compounds.

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8. Bicompounds

Bicompounds refer to organic compounds containing two distinct functional groups. These compounds exhibit properties and reactivities influenced by the presence of both functional groups.

Examples

• Amino Acids: Contain both amino (-NH2) and carboxyl (-COOH) groups.
• Hydroxy Acids: Contain both hydroxyl (-OH) and carboxyl (-COOH) groups.

The presence of two functional groups in bicompounds often leads to unique reactivity patterns. For example, amino acids can act as both acids and bases, enabling them to form peptide bonds in proteins. Similarly, hydroxy acids can participate in esterification and oxidation reactions.

Tip for Easy Remembering

Remember “DFG” (Distinct Functional Groups) to recall that bicompounds have two different functional groups.

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9. Unsaturated Hydrocarbons

Unsaturated hydrocarbons are organic compounds containing one or more double or triple bonds between carbon atoms. These compounds are classified into alkenes (with double bonds) and alkynes (with triple bonds). They have fewer hydrogen atoms compared to saturated hydrocarbons.

Examples

• Ethene (C2H4): The simplest alkene with one double bond.
• Propyne (C3H4): An alkyne with one triple bond.

Unsaturated hydrocarbons are more reactive than saturated hydrocarbons due to the presence of double and triple bonds. They undergo addition reactions, where reactants add to the multiple bonds, and polymerization reactions, where monomers join to form polymers. Unsaturated hydrocarbons are important in the production of plastics, synthetic fibers, and other industrial materials.

Tip for Easy Remembering

Use the acronym “DAU” (Double or triple bonds, Alkenes, Alkynes, Unsaturated) to recall that unsaturated hydrocarbons have double or triple bonds.

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10. Alkanes

Alkanes are saturated hydrocarbons with single bonds between carbon atoms. They follow the general formula CnH2n+2 and are also known as paraffins. Alkanes are the simplest type of hydrocarbons and serve as the foundation for understanding more complex organic compounds.

Examples

• Methane (CH4): The simplest alkane.
• Ethane (C2H6): A two-carbon alkane.
• Propane (C3H8): A three-carbon alkane.

Alkanes are relatively inert due to the strong C-C and C-H bonds, making them less reactive than other hydrocarbons. They undergo combustion reactions, producing carbon dioxide and water, and can also participate in substitution reactions with halogens. Alkanes are found in natural gas, petroleum, and are used as fuels, solvents, and lubricants.

Tip for Easy Remembering

Remember “SAH” (Saturated Alkanes Hydrocarbons) to recall that alkanes are saturated hydrocarbons with single bonds.

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11. Alkenes

Alkenes are unsaturated hydrocarbons containing one or more carbon-carbon double bonds. They follow the general formula CnH2n and are also known as olefins. The presence of double bonds gives alkenes unique chemical properties and reactivity compared to alkanes.

Examples

• Ethene (C2H4): The simplest alkene with one double bond.
• Propene (C3H6): An alkene with three carbon atoms and one double bond.
• But-2-ene (C4H8): An alkene with four carbon atoms and a double bond between the second and third carbons.

Alkenes are more reactive than alkanes due to the presence of the double bond, which is a site of high electron density. They undergo addition reactions, where atoms or groups add across the double bond, and polymerization reactions, where monomers join to form polymers. Alkenes are used in the production of plastics, synthetic fibers, and other industrial materials.

Tip for Easy Remembering

Use the mnemonic “DUB” (Double bonds, Unsaturated, Alkenes) to remember that alkenes have double bonds and are unsaturated hydrocarbons.

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12. Alkynes

Alkynes are unsaturated hydrocarbons containing one or more carbon-carbon triple bonds. They follow the general formula CnH2n-2 and are also known as acetylenes. The presence of triple bonds gives alkynes distinct chemical properties and reactivity compared to alkanes and alkenes.

Examples

• Ethyne (C2H2): The simplest alkyne with one triple bond.
• Propyne (C3H4): An alkyne with three carbon atoms and one triple bond.
• But-2-yne (C4H6): An alkyne with four carbon atoms and a triple bond between the second and third carbons.

Alkynes are more reactive than alkanes and alkenes due to the presence of the triple bond, which is a site of high electron density. They undergo addition reactions, where atoms or groups add across the triple bond, and can be reduced to alkenes and alkanes. Alkynes are used in the production of synthetic chemicals, pharmaceuticals, and as welding gases (e.g., acetylene).

Tip for Easy Remembering

Use the mnemonic “TUA” (Triple bonds, Unsaturated, Alkynes) to remember that alkynes have triple bonds and are unsaturated hydrocarbons.

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13. Nomenclature of Hydrocarbons

The nomenclature of hydrocarbons involves naming organic compounds based on their structure, including the number of carbon atoms, the type of bonds (single, double, or triple), and the presence of any substituents or functional groups. The IUPAC system provides a standardized method for naming hydrocarbons.

Examples

• Methane (CH4): The simplest alkane.
• Ethene (C2H4): The simplest alkene with one double bond.
• Propyne (C3H4): An alkyne with one triple bond.

The IUPAC nomenclature involves several steps:

1. Identify the longest carbon chain.
2. Number the carbon atoms in the chain, starting from the end closest to a substituent or multiple bond.
3. Name the substituents and assign their position numbers.
4. Combine the substituents’ names and positions with the base name of the compound.

Tip for Easy Remembering

Remember the acronym “ILNC” (Identify, Longest chain, Numbering, Combine) to recall the steps of IUPAC nomenclature for hydrocarbons.

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14. Nomenclature of Unbranched Alkanes

The nomenclature of unbranched alkanes follows a straightforward approach where the name is based on the number of carbon atoms in the longest continuous chain. The prefix indicates the number of carbon atoms, and the suffix “-ane” denotes that it is an alkane.

Examples

• Methane (CH4): One carbon atom.
• Ethane (C2H6): Two carbon atoms.
• Propane (C3H8): Three carbon atoms.
• Butane (C4H10): Four carbon atoms.

Unbranched alkanes, also known as straight-chain alkanes, have a simple structure with all carbon atoms connected in a single, continuous chain. The names are derived from a series of prefixes based on Greek or Latin numbers.

Tip for Easy Remembering

Use the mnemonic “MEPB” (Methane, Ethane, Propane, Butane) to recall the first four unbranched alkanes.

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15. Nomenclature of Branched Hydrocarbons

The nomenclature of branched hydrocarbons involves identifying the longest carbon chain and naming the branches or substituents attached to it. The IUPAC system assigns position numbers to indicate the location of each branch.

Examples

• 2-Methylpropane (CH3CH(CH3)CH3): A propane chain with a methyl group attached to the second carbon.
• 3-Ethylhexane (CH3CH2CH2CH(CH2CH3)CH2CH3): A hexane chain with an ethyl group attached to the third carbon.

To name branched hydrocarbons:

1. Identify the longest continuous carbon chain.
2. Number the carbon atoms in the chain from the end nearest a substituent.
3. Name each substituent and assign a position number.
4. Combine the names and positions of the substituents with the base name of the compound, using hyphens and commas as needed.

Tip for Easy Remembering

Use the acronym “LBNS” (Longest chain, Branches, Numbering, Substituents) to recall the steps for naming branched hydrocarbons.

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16. Nomenclature of Hydrocarbons with More Than One Branch

When naming hydrocarbons with more than one branch, the IUPAC system requires identifying the longest carbon chain and naming each branch or substituent. The position numbers indicate the location of each branch, and multiple substituents are listed in alphabetical order.

Examples

• 2,3-Dimethylbutane (CH3CH(CH3)CH(CH3)CH3): A butane chain with methyl groups attached to the second and third carbons.
• 3-Ethyl-2-methylpentane (CH3CH2CH(CH2CH3)CH(CH3)CH3): A pentane chain with an ethyl group on the third carbon and a methyl group on the second carbon.

To name hydrocarbons with more than one branch:

1. Identify the longest continuous carbon chain.
2. Number the carbon atoms in the chain from the end nearest a substituent.
3. Name each substituent and assign a position number.
4. List the substituents in alphabetical order, using prefixes like “di-“, “tri-“, and “tetra-” for multiple identical groups.
5. Combine the names and positions of the substituents with the base name of the compound, using hyphens and commas as needed.

Tip for Easy Remembering

Remember “LBNSA” (Longest chain, Branches, Numbering, Substituents, Alphabetical order) to recall the steps for naming hydrocarbons with more than one branch.

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17. Nomenclature of Unsaturated Hydrocarbons

The nomenclature of unsaturated hydrocarbons involves naming compounds with double or triple bonds. Alkenes have one or more double bonds, while alkynes have one or more triple bonds. The IUPAC system assigns position numbers to indicate the location of the multiple bonds.

Examples

• Ethene (C2H4): The simplest alkene with one double bond.
• Propyne (C3H4): An alkyne with one triple bond.
• But-2-ene (C4H8): An alkene with a double bond between the second and third carbons.

To name unsaturated hydrocarbons:

1. Identify the longest carbon chain containing the double or triple bond.
2. Number the carbon atoms in the chain from the end nearest the multiple bond.
3. Name the base compound (alkene or alkyne) and assign the position number of the multiple bond.
4. Name and position any substituents attached to the main chain.

Tip for Easy Remembering

Use the mnemonic “MDBS” (Multiple bonds, Double or triple, Base name, Substituents) to remember the steps for naming unsaturated hydrocarbons.

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18. Cyclic or Ring Compounds

Cyclic or ring compounds are organic molecules where carbon atoms are connected in a closed loop or ring. These compounds can be saturated (cycloalkanes) or unsaturated (cycloalkenes, cycloalkynes, and aromatic compounds).

Examples

• Cyclohexane (C6H12): A six-carbon saturated ring.
• Cyclopentene (C5H8): A five-carbon ring with one double bond.
• Benzene (C6H6): A six-carbon ring with alternating double bonds (aromatic).

Cyclic compounds exhibit unique properties due to the ring structure, such as ring strain in small rings and aromaticity in certain unsaturated rings. The nomenclature involves prefixing the name with “cyclo-” and numbering the ring to give substituents the lowest possible position numbers.

Tip for Easy Remembering

Remember “Rings Cyclo” (Ring compounds are prefixed with “cyclo-“) to recall that cyclic compounds are named with the “cyclo-” prefix.

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19. Alicyclic Hydrocarbons

Alicyclic hydrocarbons are cyclic compounds that resemble alkanes in their properties and follow similar naming conventions. These compounds can be saturated or unsaturated but do not exhibit aromaticity.

Examples

• Cyclohexane (C6H12): A saturated alicyclic hydrocarbon.
• Cyclopentene (C5H8): An unsaturated alicyclic hydrocarbon with one double bond.

Alicyclic hydrocarbons are named by prefixing the base name of the alkane, alkene, or alkyne with “cyclo-” and numbering the ring to assign the lowest possible position numbers to substituents. These compounds are common in natural products and synthetic materials.

Tip for Easy Remembering

Use the mnemonic “ACNC” (Alicyclic, Cyclo, Non-aromatic, Compounds) to recall that alicyclic hydrocarbons are non-aromatic cyclic compounds named with the “cyclo-” prefix.

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20. Aromatic Hydrocarbons

Aromatic hydrocarbons, also known as arenes, are cyclic compounds with alternating double bonds that follow Hückel’s rule (4n+2 π electrons). Benzene is the simplest aromatic hydrocarbon and serves as the parent compound for many derivatives.

Examples

• Benzene (C6H6): The simplest aromatic hydrocarbon.
• Toluene (C6H5CH3): A benzene ring with a methyl group.
• Naphthalene (C10H8): Two fused benzene rings.

Aromatic compounds are highly stable due to delocalized π-electrons. They undergo substitution reactions rather than addition reactions to maintain aromaticity. Aromatic hydrocarbons are widely used in the chemical industry, pharmaceuticals, and as solvents.

Tip for Easy Remembering

Remember “HAC” (Hückel’s rule, Aromatic, Cyclic) to recall that aromatic hydrocarbons follow Hückel’s rule and are cyclic with alternating double bonds.

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21. Functional Groups

Functional groups are specific groups of atoms within molecules that determine the chemical properties and reactivity of those molecules. Identifying functional groups is essential for understanding organic chemistry and predicting the behavior of organic compounds.

Examples

• Hydroxyl group (-OH): Found in alcohols.
• Carboxyl group (-COOH): Found in carboxylic acids.
• Amino group (-NH2): Found in amines.

Functional groups define the class of organic compounds and are often the sites of chemical reactions. They influence the physical properties (such as boiling and melting points) and the chemical reactivity of the molecules. Recognizing functional groups is crucial for naming compounds and understanding their behavior in chemical reactions.

Tip for Easy Remembering

Use the mnemonic “HARAC” (Hydroxyl, Amino, Carboxyl, Functional groups) to recall some of the common functional groups and their importance in organic chemistry.

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22. Hydroxyl Group

The hydroxyl group (-OH) is a functional group consisting of an oxygen atom bonded to a hydrogen atom. It is characteristic of alcohols and phenols, imparting hydrophilic properties and making compounds soluble in water.

Examples

• Methanol (CH3OH): The simplest alcohol with one hydroxyl group.
• Ethanol (CH3CH2OH): A common alcohol found in beverages.
• Phenol (C6H5OH): A benzene ring with a hydroxyl group.

The hydroxyl group is polar, forming hydrogen bonds with water molecules, which increases the solubility of alcohols and phenols. Alcohols can undergo various chemical reactions, such as oxidation, dehydration, and substitution.

Tip for Easy Remembering

Remember “OH” (Oxygen-Hydrogen) to recall that the hydroxyl group consists of an oxygen atom bonded to a hydrogen atom.

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23. Carboxyl Group

The carboxyl group (-COOH) is a functional group consisting of a carbonyl group (C=O) and a hydroxyl group (-OH) bonded to the same carbon atom. It is characteristic of carboxylic acids, imparting acidic properties.

Examples

• Acetic acid (CH3COOH): The main component of vinegar.
• Formic acid (HCOOH): Found in ant venom.
• Benzoic acid (C6H5COOH): Used as a food preservative.

The carboxyl group is acidic because it can donate a proton (H+) in aqueous solution, forming a carboxylate ion (R-COO-). Carboxylic acids undergo various reactions, such as esterification, reduction, and substitution.

Tip for Easy Remembering

Remember “COOH” (Carbonyl-Oxygen-Oxygen-Hydrogen) to recall that the carboxyl group consists of a carbonyl group and a hydroxyl group bonded to the same carbon atom.

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24. Halo Group

The halo group consists of halogen atoms (fluorine, chlorine, bromine, or iodine) bonded to a carbon atom. Organic compounds containing halo groups are called haloalkanes or alkyl halides.

Examples

• Chloromethane (CH3Cl): A simple haloalkane with a chlorine atom.
• Bromoethane (C2H5Br): A haloalkane with a bromine atom.
• Iodoform (CHI3): A haloalkane with three iodine atoms.

Haloalkanes are reactive due to the presence of the halogen atom, which can undergo substitution or elimination reactions. They are used in various industrial applications, such as solvents, refrigerants, and pharmaceuticals.

Tip for Easy Remembering

Remember “HaX” (Halo-X, where X is a halogen) to recall that halo groups consist of halogen atoms bonded to a carbon atom.

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25. Alkoxy Group

The alkoxy group (-OR) is a functional group consisting of an oxygen atom bonded to an alkyl group (R). It is characteristic of ethers, where two alkyl or aryl groups are bonded to the oxygen atom.

Examples

• Methoxy group (-OCH3): Found in methanol.
• Ethoxy group (-OCH2CH3): Found in ethanol.
• Phenoxy group (-OC6H5): Found in phenol.

Ethers are generally less reactive than alcohols and are used as solvents in organic reactions. The alkoxy group imparts hydrophobic properties and can influence the boiling points and solubility of ethers.

Tip for Easy Remembering

Remember “OR” (Oxygen-R, where R is an alkyl group) to recall that the alkoxy group consists of an oxygen atom bonded to an alkyl group.

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26. Isomerism

Isomerism is the phenomenon where two or more compounds have the same molecular formula but different structures or spatial arrangements of atoms. Isomers can have distinct physical and chemical properties, making isomerism a critical concept in organic chemistry.

Types of Isomerism

• Structural Isomerism: Compounds with different connectivity of atoms.
  • Chain Isomerism: Different carbon chain arrangements.
  • Position Isomerism: Different positions of a functional group.
  • Functional Isomerism: Different functional groups.
• Stereoisomerism: Compounds with the same connectivity but different spatial arrangements.
  • Geometric Isomerism: Different arrangements around a double bond (cis/trans).
  • Optical Isomerism: Non-superimposable mirror images (enantiomers).

Examples

• Structural Isomers: Butane (C4H10) and isobutane (C4H10).
• Geometric Isomers: cis-2-butene and trans-2-butene.
• Optical Isomers: Lactic acid (CH3CH(OH)COOH) enantiomers.

Isomerism plays a crucial role in the properties and reactivity of organic compounds. Structural isomers may have different boiling points, melting points, and densities, while stereoisomers can have different optical activities and biological activities.

Tip for Easy Remembering

Remember “SISO” (Structural and Stereoisomerism) to recall the two main types of isomerism and their subtypes.– versatile in acid-base, redox, and precipitation processes.