Saturated hydrocarbons also known as alkanes contain only a single covalent bonds between carbon atoms. The common feature found in all saturated hydrocarbons is carbon-carbon multiple bonds.
Unsaturated hydrocarbons are hydrocarbons in which all the valencies of carbon atoms are not fully utilized by single covalent bonds. They contain at least one double or triple bond in their structure.
Characteristic reactions of alkanes or saturated hydrocarbons are substitution reactions. Unsaturated hydrocarbons characteristics reactions are addition reactions.
