1. Hydrocarbons
1.1 Classification of Organic Compounds
Organic compounds are primarily made of carbon and hydrogen, sometimes including oxygen, nitrogen, sulfur, and halogens.
Functional groups determine the chemical properties and behavior of organic compounds.
Homologous series: A family of compounds with the same general formula, differing by CH₂ groups.
1.2 Alkanes (Saturated Hydrocarbons)
General Formula: C_nH_(2n+2)
Structure & Bonding:
Alkanes contain only single sigma (σ) bonds.
They adopt a tetrahedral shape around each carbon with bond angles of 109.5°.
Nomenclature:
Follows IUPAC naming conventions for straight and branched alkanes.
Physical Properties:
Non-polar, insoluble in water, low reactivity.
Boiling points increase with molecular size due to stronger van der Waals forces.
Reactions:
Combustion:
Complete: Produces CO₂ and H₂O.
Incomplete: Produces CO or C (soot) and H₂O.
Halogenation:
Requires UV light.
Free radical substitution (Initiation, Propagation, Termination steps).
Example: CH₄ + Cl₂ → CH₃Cl + HCl.
1.3 Alkenes (Unsaturated Hydrocarbons)
General Formula: C_nH_2n
Structure & Bonding:
Contain one or more double bonds (σ and π bonds).
Trigonal planar geometry, bond angle of 120°.
Nomenclature:
Follows IUPAC naming conventions, with numbering of the double bond.
Preparation:
Dehydration of alcohols using concentrated H₂SO₄ at 170°C.
Dehydrohalogenation of haloalkanes using alcoholic KOH.
Saytzeff’s Rule:
In elimination reactions, the major product is the more substituted alkene.
Addition Reactions:
Hydrogenation: Addition of H₂ (Ni catalyst, 150°C).
Halogenation: Addition of Cl₂ or Br₂.
Hydrohalogenation: Follows Markovnikov’s Rule (H attaches to the carbon with more H’s).
Hydration: Addition of H₂O (H₃O⁺ catalyst) to form alcohols.
