Standardizing Carbon Compound Nomenclature: IUPAC Rules for Global Uniformity

• The International Union of Pure and Applied Chemistry (IUPAC) decided on some rules for naming carbon compounds. This was done to maintain uniformity throughout the world.

Exploring Homologous Series: Patterns and Variations in Organic Compounds 

• Meaning: Homologous series constitutes organic compounds with the same general formula, and similar chemical characteristics but different physical properties. 
  • The adjacent members differ in their molecular formula by −CH₂. 
  • Example: Methane, ethane, propane, butane, etc. are all part of the alkane homologous series.
    • The general formula of this series is CnH_2n+2.
    • Methane (CH₄), Ethane (CH₃CH₃), Propane (CH₃CH₂CH₃), Butane (CH₃CH₂CH₂CH₃).
  • It can be noticed that there is a difference of −CH₂ units between each successive compound.

The Chemical Dynamics: Exploring Combustion, Oxidation, and Reactions in Carbon Compounds

• Combustion Reactions: Combustion means the burning of carbon or carbon-containing compounds in the presence of air or oxygen to produce carbon dioxide, heat and light.

• • • 2CH₃OH + 3O₂ → 4H₂O + 2CO₂
  • Saturated hydrocarbons give a clean flame, while unsaturated hydrocarbons give a smoky flame. 
  • In the presence of limited oxygen, even saturated hydrocarbons give smoky flame.
  • Soot: It is a black substance formed by combustion or separated from fuel during combustion, rising in fine particles and adhering to the sides of the chimney or pipe conveying the smoke especially, i.e., the fine powder consisting chiefly of carbon that colours smoke. 

• Oxidation:  Oxidation is a chemical reaction that occurs in an atom or compound and results in the loss of one or more electrons.

• Addition: The reactions in which two molecules react to form a single product having all the atoms of the combining molecules are called addition reactions.

• • The hydrogenation reaction is an example of the addition reaction. 
  • In this reaction, hydrogen is added to a double bond or a triple bond in the presence of a catalyst like nickel, palladium or platinum.

• Substitution: The reaction in which an atom or group of atoms in a molecule is replaced or substituted by different atoms or groups of atoms is called a substitution reaction. 
  • In alkanes, hydrogen atoms are replaced by other elements.

Exploring the Properties and Reactions of Ethanol and Ethanoic Acid: From Solvents to Chemical Transformations

• Ethanol: Ethanol or C₂H₅OH is a colourless liquid having a pleasant smell.

• • It boils at 351 K.
  • It is miscible with water in all proportions.
  • It is a non-conductor of electricity (it does not contain ions)
  • It is neutral to litmus.

• Uses: Ethanol is used as an antifreeze in radiators of vehicles in cold countries.

• • It is also used as a solvent in the manufacture of paints, dyes, medicines, soaps and synthetic rubber. It is also used as a solvent to prepare the tincture of iodine.

• Reactions of Ethanol with Sodium: Ethanol reacts with sodium to produce hydrogen gas and sodium ethoxide. This reaction supports the acidic character of ethanol.

2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂(↑)

• Reactions to give Unsaturated Hydrocarbon (Dehydration of Ethanol): Ethanol reacts with concentrated sulphuric acid at 443 K to produce ethylene. This reaction is known as dehydration of ethanol because, in this reaction, a water molecule is removed from the ethanol molecule.

CH₃CH₂OH → CH₂=CH₂ + H₂O

• • Ethanol Acid: With molecular formula given as CH₃COOH, it dissolves in water, alcohol and ether.
    • It often freezes during winter in a cold climate, and therefore, it is named glacial acetic acid.

• Exploring Ethanoic Acid Reactions and the Science Behind Soaps and Detergents

• • Esterification: When a carboxylic acid is refluxed with alcohol in the presence of a small quantity of conc. H₂SO₄, a sweet-smelling ester is formed. 
    • This reaction of ester formation is called esterification.
  • Saponification: On treatment with sodium hydroxide, which is an alkali, the ester is converted back to alcohol and sodium salt of carboxylic acid. 
    • This reaction is known as saponification because it is used in the preparation of soap. 

• • Soaps are sodium or potassium salts of long chain carboxylic acid. 
  • Reaction with a Base: Like mineral acids, ethanoic acid reacts with a base such as sodium hydroxide to give a salt (sodium ethanoate or commonly called sodium acetate) and water:

NaOH + CH₃COOH → CH₃COONa + H₂O

• Reaction with Carbonates and Hydrogen Carbonates: Ethanol acid reacts with carbonates and hydrogen carbonates to give rise to salt, carbon dioxide and water. 
  • The salt produced is commonly called sodium acetate.

2CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O + CO₂

CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂

• Soaps and Detergents: Most dirt is oily in nature and oil does not dissolve in water. 
  • The molecules of soap are sodium or potassium salts of long-chain carboxylic acids.  
  • The ionic-end of soap interacts with water while the carbon chain interacts with oil. 
  • Micelles: The soap molecules, thus form structures called micelles where one end of the molecules is towards the oil droplet while the ionic-end faces outside.
  • Emulsion: This forms an emulsion in water. The soap micelle thus helps in pulling out the dirt in water and we can wash our clothes clean  
  • Properties: Soaps are molecules in which the two ends have differing properties, one is hydrophilic, that is, it interacts with water, while the other end is hydrophobic, that is, it interacts with hydrocarbons. 
  • Soap on Surface: When soap is at the surface of water, the hydrophobic ‘tail’ of soap will not be soluble in water and the soap will align along the surface of water with the ionic end in water and the hydrocarbon ‘tail’ protruding out of water.
  • Soap Inside Water: Inside water, these molecules have a unique orientation that keeps the hydrocarbon portion out of the water. 
    • Thus, clusters of molecules in which the hydrophobic tails are in the interior of the cluster and the ionic ends are on the surface of the cluster.
    • This formation is called a micelle. 
  • Soap in the form of a micelle is able to clean, since the oily dirt will be collected in the center of the micelle. 
  • Repulsion: The micelles stay in solution as a colloid and will not come together to precipitate because of ion-ion repulsion.
    • Thus, the dirt suspended in the micelles is also easily rinsed away. 
  • The soap micelles are large enough to scatter light. Hence a soap solution appears cloudy.

Conclusion

• Carbon is a versatile element that forms the basis for all living organisms and many of the things we use. 
  • Carbon forms covalent bonds with itself and other elements such as hydrogen, oxygen, sulphur, nitrogen and chlorine. Carbon and its compounds are some of our major sources of fuels. Ethanol and ethanoic acid are carbon compounds of importance in our daily lives. 
  • The action of soaps and detergents is based on the presence of both hydrophobic and hydrophilic groups in the molecule and this helps to emulsify the oily dirt and hence its removal

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