Organic Basics
Chemistry · कार्बनिक रसायन
📋Quick Overview
Organic chemistry is the study of carbon compounds. Carbon is unique because it has 4 valence electrons and can form 4 covalent bonds, creating chains, branches, and rings (catenation). Friedrich Wohler (1828) synthesized urea from ammonium cyanate, disproving the 'vital force theory'. Hydrocarbons (compounds of C and H only) are classified as alkanes, alkenes, and alkynes.
📖Hydrocarbons — Alkanes, Alkenes, Alkynes
| Type | General Formula | Bond Type | Suffix | First Member | Example |
|---|---|---|---|---|---|
| Alkanes (Saturated) | CₙH₂ₙ₊₂ | Single bond (C-C) | -ane | Methane (CH₄) | Ethane C₂H₆, Propane C₃H₈ |
| Alkenes (Unsaturated) | CₙH₂ₙ | Double bond (C=C) | -ene | Ethene (C₂H₄) | Propene C₃H₆, Butene C₄H₈ |
| Alkynes (Unsaturated) | CₙH₂ₙ₋₂ | Triple bond (C≡C) | -yne | Ethyne (C₂H₂) = Acetylene | Propyne C₃H₄ |
📖Homologous Series
- •A series of organic compounds with the same general formula and functional group, differing by CH₂
- •Each next member differs by CH₂ (= 14 mass units)
- •Same chemical properties, physical properties change gradually (MP, BP increase)
- •Example: CH₄ → C₂H₆ → C₃H₈ → C₄H₁₀ (alkane series)
📖Functional Groups
| Functional Group | Formula | Class of Compounds | Example |
|---|---|---|---|
| Hydroxyl | -OH | Alcohols | Methanol (CH₃OH), Ethanol (C₂H₅OH) |
| Aldehyde | -CHO | Aldehydes | Formaldehyde (HCHO), Acetaldehyde (CH₃CHO) |
| Carboxyl | -COOH | Carboxylic Acids | Acetic acid (CH₃COOH), Formic acid (HCOOH) |
| Ketone | >C=O | Ketones | Acetone (CH₃COCH₃) |
| Amino | -NH₂ | Amines | Methylamine (CH₃NH₂) |
| Halide | -X (F, Cl, Br, I) | Haloalkanes | Chloroform (CHCl₃), Chloromethane (CH₃Cl) |
📖Important Organic Compounds
| Compound | Formula | Key Facts |
|---|---|---|
| Methanol (Wood spirit) | CH₃OH | Poisonous, causes blindness/death. Used as industrial solvent. |
| Ethanol (Grain alcohol) | C₂H₅OH | Present in alcoholic drinks. Used as fuel (biofuel), solvent. Denatured alcohol = ethanol + methanol. |
| Acetic acid (Vinegar) | CH₃COOH | 5-8% solution = vinegar. Used in food preservation, making esters. |
| Methane | CH₄ | Simplest hydrocarbon, main component of natural gas, biogas, marsh gas. |
| Acetylene (Ethyne) | C₂H₂ | Used in oxy-acetylene welding torch (very hot flame 3000°C). |