Carbon forms a number of compounds due to its salient properties.
Methane (CH4) is the most general or basic compound.
Hydrocarbon is the compound made up of just hydrogen and carbon and so methane is a hydrocarbon.
Hydrogen + Carbon = Hydrocarbon
As ethane (C2H6), ethylene (C2H4), and ethyne (C2H2), are other hydrocarbons as they are made up of only two elements: Carbon and Hydrogen, they are called as Hydrocarbons.
The most important natural source of hydrocarbons is petroleum (or crude oil).
The molecular formula of such compounds can be easily determined by adding hydrogen to satisfy the valency of carbon atoms.
For example: ethane has two carbon atoms. So 6 hydrogen atoms are required to satisfy the valency of each carbon atom. Hence the molecular formula for ethane is C2H6.
TYPES OF HYDROCARBONS
Hydrocarbons are of two types:
Saturated hydrocarbons and
Unsaturated hydrocarbons.
SATURATED HYDROCARBONS (ALKANES)
In Saturated hydrocarbon the carbon atoms are connected by only single bonds. 4
ALKANES
Saturated hydrocarbons are also known as alkanes.
There are no double or triple bonds in an alkane as alkane is a saturated hydrocarbon in which the carbon atoms are connected by only single covalent bonds
The hydrocarbons methane, ethane, propane and butane form a series of compounds known as alkanes. The structure of ethane is shown below:
Naming Convention: The names of all these saturated hydrocarbons end with ‘ane’.
Formula: The saturated hydrocarbons or alkane is represented as: CnH2n+2Where n is the number of carbon atoms is one molecule of the alkane.
UNSATURATED HYDROCARBONS (ALKENES AND ALKYNES)
In Unsaturated hydrocarbon two carbon atoms are connected by a ‘double bond’ or a ‘triple bond’.
Unsaturated hydrocarbons are of two types:
Alkenes: Those containing carbon-carbon double bonds.
Alkynes: Those containing carbon-carbon triple bonds.
ALKENES
An alkene is an unsaturated hydrocarbon where two carbon atoms are connected by a soluble bond.
Alkene has a double bond between two carbon atoms. So, it is obvious that the simplest alkene will have two carbon atoms in its molecules.
Hence, there can be no alkene having only one carbon atom.
Formula: The general formula of an alkene is CnH2n , where n is the number of carbon atoms in its one molecule.
The simplest alkene is ethene having the molecular formula. The common name of ethene is ethylene.
ALKYNES
Alkyne is an unsaturated hydrocarbon where two carbon atoms connect to form a triple bond..
Formula: The general formula of alkynes is CnH2n-2, where n is the number of carbon atoms in one molecule of the alkyne.
The simplest alkyne is ethyne having the molecular formula. The common name of ethyne is acetylene.