Alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond. They have lower melting and boiling points than alkanes due to weaker intermolecular forces and are soluble in organic solvents but not water. Alkenes undergo combustion reactions, addition reactions, and polymerization reactions. They react with bromine water and potassium permanganate solution, showing characteristics of alkenes.

1. Defination : -Unsaturated hydrocarbon -Have Unless 1 double bond C=C C n H 2n n= 2,3,4….. H H H H Physical properties : Low melting and boiling points soluble in organic solvent insoluble in water Less dense than water. cannot conduct electricity Chemical properties: -Combustion reaction C 2 H 4 (g) + 3O 2 (g) 2CO 2 +2H 2 O -Addition reaction C 2 H 4 (g) + A-B C 2 H 4 AB - Polimerization reaction Alkene molecules undergo addition reaction with one another Compare and contrast alkanes and alkenes -Sootines of flame -Reaction with bromine -Reaction with KMnO 4 Characteristics of homologous series -has a general formula -differ from each other by –CH 2 -prepared by similar methods -physical properties change with increasing number of carbon ALKENES C=C The molecular formulae, Name an structural formulae Example : C 2 H 4 – Ethene C=C H H H H