Hydrocarbons are compounds of hydrogen and carbon. Both the elements combine in various proportions, giving rise to a large number of hydrocarbons like methane, butane, benzene, etc. hydrocarbons are of two kinds, saturated and unsaturated.

Saturated hydrocarbons:

In saturated hydrocarbons, the carbon atoms are connected only by single bonds.


Saturated hydrocarbons are grouped under the general name, alkanes or paraffins. The general formula for alkanes is CnH2n+2, where n is the number of carbon atoms in a molecule of the alkane.

Unsaturated hydrocarbons:

In unsaturated hydrocarbons, the adjacent carbon atoms are joined by double or triple bonds.

  • When the molecule contains a double bond, the compound is called an alkene. The general formula of alkenes is CnH2n. Ethylene or ethane, is the simplest alkene. They are also called olefins.
  • In case there is a triple bond present, the compound is called an alkyne. The simplest alkyne is ethyne (C2H2). Commercially known as acetylene.

Alkynes are represented by the general formula CnH2n-2.