organic chemistry

1. Alkanes

Saturated hydrocarbons consisting only of carbon (CC) and hydrogen (HH) atoms.

  • General Formula: C<em>nH</em>2n+2C<em>n H</em>{2n+2}

  • Key Properties: Saturated (only single bonds between carbon atoms).

  • Key Reactions:

    • Combustion: Burns in oxygen to produce CO<em>2CO<em>2 and H</em>2OH</em>2 O.

    • Substitution: Reacts with halogens (e.g., CH<em>4+Cl</em>2→CH3Cl+HClCH<em>4 + Cl</em>2 \rightarrow CH_3 Cl + HCl) typically in the presence of UV light.

2. Alkenes

Unsaturated hydrocarbons with at least one carbon-carbon double bond (C=CC=C).

  • General Formula: C<em>nH</em>2nC<em>n H</em>{2n}

  • Key Reaction:

    • Addition: Halogens (like bromine) add across the double bond (e.g., C=C+Br2→C−CC=C + Br_2 \rightarrow C-C). This is used as a test for unsaturation; bromine water turns from orange to colorless.

3. Isomers

Compounds with the same molecular formula but different structural formulas.

  • Chain Isomers: Different arrangements of the carbon backbone.

  • Functional Group Isomers: Same atoms rearranged into different functional groups.

4. Functional Groups and Nomenclature

  • Alkane: Contains C−CC-C bonds, suffix -ane.

  • Alkene: Contains C=CC=C bonds, suffix -ene.

  • Alcohol: Contains −OH-OH group, suffix -ol.

  • Carboxylic Acid: Contains −COOH-COOH group, suffix -oic acid.

  • Naming: Identify the longest carbon chain first, then the functional groups.

5. Homologous Series

A series of compounds with the same functional group and similar chemical properties, where each successive member differs by a CH2CH_2 unit.

6. Fractional Distillation of Crude Oil

A process to separate crude oil into fractions based on boiling points.

  • Trends: Smaller hydrocarbons have lower boiling points, higher volatility, and lower viscosity.

  • Main Fractions: Gases, Petrol, Kerosene, Diesel, Heavy fuels, and Bitumen.

7. Cracking

The thermal decomposition of long-chain hydrocarbons into shorter, more useful chain hydrocarbons and alkenes.

  • Conditions: High temperatures (600−700∘C600-700^{\circ}C).

  • Catalysts: Silica (SiO<em>2SiO<em>2) or alumina (Al</em>2O3Al</em>2 O_3).

8. Reactions of Alcohols and Carboxylic Acids

  • Alcohol Oxidation: Oxidation of alcohols produces carboxylic acids.

  • Carboxylic Acid Reactions:

    • Acid+Base→Salt+H2O\text{Acid} + \text{Base} \rightarrow \text{Salt} + H_2 O

    • Acid+Carbonate→Salt+H<em>2O+CO</em>2\text{Acid} + \text{Carbonate} \rightarrow \text{Salt} + H<em>2 O + CO</em>2