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Ethanol: Carbon compound, Chemistry, Reactions, and Practical Applications

December 18, 2023 714 0

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 CnH2n+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.

Formation of coal and petroleum

  • Coal and petroleum have been formed from biomass which has been subjected to various biological and geological processes. Coal is the remains of trees, ferns, and other plants that lived millions of years ago.
  • These were crushed into the earth, perhaps by earthquakes or volcanic eruptions. They were pressed down by layers of earth and rock. They slowly decayed into coal.
  • Oil and gas are the remains of millions of tiny plants and animals that lived in the sea. When they died, their bodies sank to the sea bed and were covered by silt. Bacteria attacked the dead remains, turning them into oil and gas under the high pressures they were being subjected to.
  • Meanwhile, the silt was slowly compressed into rock. The oil and gas seeped into the porous parts of the rock, and got trapped like water in a sponge.

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.

Oxidation

  • 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.

Addition

  • 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.

Substitution

Why do substances burn with or without a flame?
This is because a flame is only produced when gaseous substances burn. When wood or charcoal is ignited, the volatile substances present evaporate and burn with a flame in the beginning.
A luminous flame is seen when the atoms of the gaseous substance are heated and start to glow. The color produced by each element is a characteristic property of that element.

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. 

Esterification

    • 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.

 Formation of Micelles

How do alcohols affect living beings?

  • When large quantities of ethanol are consumed, it tends to slow metabolic processes and to depress the central nervous system. This results in lack of coordination, mental confusion, drowsiness, lowering of the normal inhibitions, and finally stupor.
  • The individual may feel relaxed without realizing that his sense of judgment, sense of timing, and muscular coordination have been seriously impaired.
  • Unlike ethanol, intake of methanol in very small quantities can cause death. Methanol is oxidized to methanol in the liver.
  • Methanol reacts rapidly with the components of cells. It coagulates the protoplasm, in much the same way an egg is coagulated by cooking.
  • Methanol also affects the optic nerve, causing blindness. Ethanol is an important industrial solvent.
  • To prevent the misuse of ethanol produced for industrial use, it is made unfit for drinking by adding poisonous substances like methanol to it.
  • Dyes are also added to color the alcohol blue so that it can be identified easily. This is called denatured alcohol.

Alcohol as a fuel

  • Sugarcane plants are one of the most efficient convertors of sunlight into chemical energy. Sugarcane juice can be used to prepare molasses which is fermented to give alcohol (ethanol).

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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UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
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