IGCSE Organic Reactions Explained with Animations

Alkenes are hydrocarbons containing a carbon-carbon double bond.The double bond creates an electron-rich region that can react with other molecules.When bromine is added to an alkene, it forms an orange solution.The bromine molecule approaches the double bond and breaks apart.Each bromine atom attaches to one of the carbons as the double bond breaks.The addition reaction follows a specific mechanism.As the bromine molecule approaches, the double bond breaks.Finally, new single bonds form with the bromine atoms.This reaction serves as a test for unsaturation. The orange bromine solution becomes colorless when it reacts with an alkene.In substitution reactions, we start with methane, CH4, and chlorine gas, Cl2.The reaction begins when UV light breaks the chlorine molecule into reactive radicals.The UV light provides energy to break the chlorine-chlorine bond, forming two chlorine radicals.A chlorine radical attacks the methane molecule, removing a hydrogen atom to form HCl and a methyl radical.The first substitution product forms when a chlorine atom replaces a hydrogen, producing methyl chloride.Further substitution can occur, replacing more hydrogen atoms with chlorine to form di-, tri-, and tetrachloromethane.As the reaction progresses in sunlight, the mixture changes from colorless to pale green.