Chemistry XI Content
Introduction to Hydrocarbons
| Alkanes are open chain saturated hydrocarbons (aliphatic hydrocarbons) in which all carbon atoms are bonded to each other by single covalent bond. Each carbon is tetrahedrally surrounded by H-atoms . Since all the valencies of carbon atoms are fully utilized by sigma bond with H-atoms therefore, they|
are also known as “SATURATED HYDROCARBONS”.
|GENERAL FORMULA: CnH2n+2|
n=number of C-atoms
| EXAMPLES : methane , ethane, propane , butane etc.|
TYPE OF REACTIONS: Characteristic reactions of alkanes are “substitution reactions”.
|alkanes are relatively chemically inert to some extent that’s why they are also called “PARAFFINS“.|
| Alkenes are open chain unsaturated hydrocarbons in which a carbon-carbon bond is a double covalent bond.|
GENERAL FORMULA : CnH2n
Where, n=number of carbon atoms and n is greater than 1.
They are very reactive organic compounds due to the presence of PI-BOND. They are also known as “OLEFINS” .
TYPE OF REACTIONS: Characteristic reactions of alkenes are “addition reactions”. EXAMPLES : ethene, propene etc.
| Alkynes are open chain unsaturated hydrocarbons in which one bond between any two carbon atoms is a triple covalent bond.|
GENERAL FORMULA: CnH2n-2
Where, n=number of C-atoms and n is greater than 1.
Alkynes are more unsaturated hydrocarbons than alkenes. They are also very reactive compounds.
TYPE OF REACTIONS:
Characteristic reactions of alkynes are “addition reactions”. EXAMPLES : ethyne, propyne etc.