Revision: Hydrocarbons Chemistry Science (English Medium) Class 11 CBSE

The compounds of carbon having double or triple bonds between the carbon atoms are known as unsaturated carbon compounds.

The valencies of all the atoms are satisfied by single bonds between them. Such carbon compounds are called saturated compounds.

Alkanes are hydrocarbons in which all the linkages between the carbon atoms are single covalent bonds.

Alkenes are compounds with at least one carbon-carbon double bond. Alkenes form a homologous series having the general formula C_n H_2n

Compounds having the same molecular formula but different structural formula are known as Isomers and the phenomenon is known as Isomerism. (iso = same, meros = parts).

The aliphatic hydrocarbons that contain a triple bond (-C = C-), i.e., acetylenic bond, between two carbon atoms are known as alkynes. The general formula C_nH_2n-2.

• Ethene is a colourless, flammable gas with a faint, sweet smell.
• It has a melting point of –169°C and boiling point of –102°C.
• Slightly soluble in water but highly soluble in organic solvents; has a mild anaesthetic effect.

• Ethene reacts with hydrogen, halogens, and acids to form saturated compounds like ethane and alcohols.
• It forms polythene through polymerisation.
• Burns with a sooty flame and gives ethylene glycol with KMnO₄.