Organic Chemistry

Organic Chemistry Basics

  • Organic Chemistry is the study of carbon-containing compounds, including hydrocarbons and their derivatives.

  • Carbon has four valence electrons, enabling it to form covalent bonds with other elements. These bonds can result in different structures like chains, branches and rings.

  • Hydrocarbons are organic compounds composed of hydrogen and carbon atoms. They’re mainly divided into alkanes, alkenes, and alkynes based on their bonding.

  • Isomers are compounds with the same molecular formula but different structural formulas.


  • Alkanes have only single bonds between the carbon atoms and follow the general formula CnH2n+2.

  • These are saturated compounds as they contain as many hydrogen atoms as possible.

  • They exhibit chain isomerism where the carbon atoms can be rearranged in different ways.

Alkenes and Alkynes

  • Alkenes have one or more carbon-carbon double bonds and follow the general formula CnH2n.

  • Alkynes have one or more carbon-carbon triple bonds and follow the general formula CnH2n-2.

  • Both alkenes and alkynes are unsaturated hydrocarbons as they contain fewer hydrogen atoms than alkanes.

  • They engage in addition reactions where the double or triple bond breaks to allow new elements to bond with the carbon atoms.

Organic Reactions

  • Combustion is a reaction of hydrocarbons with oxygen to produce carbon dioxide and water. Incomplete combustion results in carbon (soot) or carbon monoxide.

  • Substitution reactions are characteristic for alkanes where one or more hydrogen atoms are replaced with another atom or group.

  • Addition reactions are characteristic for alkenes and alkynes, where atoms are added to the carbon-carbon double or triple bonds.

  • Esterification is a reaction between carboxylic acids and alcohols to form an ester and water.

Functional Groups

  • Functional groups determine the reactivity and polarity of organic compounds.

  • Examples of functional groups are alcohol (-OH), carboxylic acid (-COOH), aldehyde (-CHO), ketone (-CO-), halide (-X), and amines (-NH2).

  • The presence of functional groups allows for a wide range of chemical reactions.


  • Polymers are large molecules made up of repeating subunits called monomers.

  • Addition polymers are formed from alkenes through an addition reaction.

  • Condensation polymers are formed when two different monomers combine, releasing a small molecule like water.

Crude Oil and Fuels

  • Crude oil is a mixture of various hydrocarbons. It’s processed through a method called fractional distillation to produce useful products like petrol, diesel, jet fuel, and gases.

  • Fossil fuels release carbon dioxide when burnt, contributing to global warming, making the search for renewable energy sources vital.