Railway Science (Chemistry-Organic Chemistry)

A homologous series is a collection of compounds with the same general formula that differ only in the carbon chain length.
For Example- CH₄ , C₂H₆ , C₃H₈ , etc. Characteristics-functional group of the members are same, general formula is same, have nearly identical chemical properties.

A collection of compounds with the same general formula that differ only in the carbon chain length. Compounds in a homologous series often have a fixed set of functional groups, resulting in chemical and physical properties that are comparable. Members of Homologous series have a general method of preparation in common.
Example: Alkanes with general formula CₙH₂ₙ₊₂, alkenes with general formula CₙH₂ₙ and alkynes with general formula CnH₂ₙ₋₂ form the most basic homologous series.

Propanone (C₃H₆O) is the first in the Ketone homologous series because methanone (CH₂O) or ethanone cannot exist as they cannot have a secondary carbonyl group.
It has only one double bond, that is present between carbon and oxygen. The second member is Butanone (C₄H₈O). 3rd member (Pentane 3-one, C₅ H₁₀O), 4th member (Hexane-3-one, C₆H₁₂O). Ketones are used as an excellent solvent in industry.

Alcohol(Ethanol, CH3CH2OH) reacts with Sodium(Na) metal to form Sodium Alkoxide(Sodium Ethoxide,𝐶₂𝐻₅ ONa) and Hydrogen Gas  (H₂).
2 CH₃CH₂OH + 2Na →2𝐶₂𝐻₅ ONa + 𝐻₂ . It shows that ethanol is acidic in 2 nature.

Heptene (C₇H₁₄) (Alkene, CₙH₂ₙ): used as an additive in lubricants, as a catalyst, and as a surfactant. Hexene (C₆H₁₂) used as a solvent, paint thinner, and chemical reaction medium. Pentene (C₅H₁₀):
used as a pesticide, as an additive to gasoline, and in the manufacture of other chemicals. Pentane (C₅H₁₂): used in the production of polystyrene foam. Heptane (C₇H₁₆): used in laboratories as a non-polar solvent.

Compounds in a homologous series often have a fixed set of functional groups, resulting in chemical and physical properties that are comparable.
Typical examples of Homologous series are alkanes (CₙH₂ₙ ₊ ₂) , alkyl (CₙH₂ₙ ₊ ₁), cycloalkanes (CₙH₂ₙ) and alkenes (CₙH₂ₙ), Alkyne (CₙH₂ₙ₋₂), and alcohols (CₙH₂ₙ ₊ ₁OH).

average mass 78.112 g/mol. The structure has a six-carbon ring which is represented by a hexagon and it includes 3-double bonds. The carbon atoms are represented by a corner that is bonded to other atoms. It was discovered by Michal Faraday in 1825.
Uses - Making plastics, synthetic fibers, rubber lubricants, dyes, resins, detergents, drugs and more. Derivatives of Benzene :- Phenol (C₆H₆O), Toulene (C₆H₅CH₃), Aniline (C₆H₅NH₂), Anisole (C₇H₈O), Benzaldehyde (C₇H₆O), Acetophenone (C₈H₈O), Benzoic Acid (C₇H₆O₂), Benzenesulphonic Acid (C₆H₆O₃S), Styrene (C₈H₈).

Acetic acid (common name)/ ethanoic acid (chemical name) (CH₃COOH) - Boiling Point (118 °C). The high molecular mass of acetic acid accounts for its high boiling point.Vinegar - At least 4% acetic acid by volume.
Methane (CH₄) - The simplest alkane, and the main constituent of natural gas. BP: -161.5 °C. Ethanol (C₂H₅OH) - an alcohol, a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. BP: 78.37 °C. Chloroform (CHCl₃) - a colorless, strong-smelling, dense liquid. BP: 61.2 °C.

Citric Acid - It is a colourless weak organic acid. It occurs naturally in citrus fruits such as lemon, Orange, Grapefruit. Acetic Acid - it is a colorless liquid organic compound which is found in vinegar. Oxalic Acid - It is a crystalline solid that dissolves in water to give colorless, acidic solutions which is found in Pepper, Spinach, Tomato.

A substance that dries or removes water from a material. In chemical reactions where dehydration occurs, the reacting molecule loses a molecule of water. Examples - Sulfuric acid, concentrated phosphoric acid, hot aluminum oxide and hot ceramic.