Organic compounds are large class of compounds which contain carbon and hydrogen as the main constituent elements. For example, sugar, fatty acids and natural rubber are organic compounds.
One important class of organic compounds is acyclic compounds. They are also called open chain compounds, due to their open chain structure. Open chain compounds contain long carbon-carbon chains.
Branching of such chains is possible. Consequently, more than one structure may be written for the same molecular formulae.
Acyclic compounds or open chain compounds can be further classified into saturated and unsaturated hydrocarbons.