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Nomenclature of Hydrocarbons
Nomenclature of Carbon Compounds
Functional groups are specific atoms, ions, or groups of atoms that have consistent properties.
In organic chemistry, apart from hydrocarbons, there are other molecules where carbon forms bonds with other elements, such as halogens, oxygen, nitrogen and sulphur.
rational system of naming carbon compounds was developed. It was modified by the International Union of Pure and Applied Chemistry (IUPAC) and is followed all over the world. According to the IUPAC system of nomenclature, the name of an organic compound consists of a root word, a suffix and a prefix.
1. For saturated hydrocarbons, the primary suffix “ane” should be added. For example, the IUPAC name of
is ethane.
2. Hydrocarbons containing double bonds are known as alkenes. For such hydrocarbons, the primary suffix “ene” should be added to the root word. For example,
the IUPAC name of 
is written as Ethene
3. Hydrocarbons that contain a triple bond between carbon atoms are known as alkynes and for naming such hydrocarbons the primary suffix “yne “should be added. For example, the IUPAC name of
is written as propyne.
A secondary suffix indicates the functional group present in the carbon compound.
For example a molecule of ethyl alcohol contains two carbon atoms, so the root word is “eth”. It is saturated so the primary suffix should be “ane” but as there is a functional group –OH in the molecule, remove the “e” from the name of the molecule and add the secondary suffix “ol”. Therefore, the IUPAC name of ethyl alcohol is “ethanol”.
Using the same set of rules, the IUPAC name of the propanaldehyde molecule can be written as Propanal, acetone can be written as propanone. Similarly, the IUPAC name of propionic acid can be written as propanoic acid.
The parts of the name that precede the root word are called prefixes. For example, in the compound, cyclobutane, “cyclo” is the prefix that indicates the alicyclic nature of the compounds
