This video lecture from Aliphatic Hydrocarbons (F.Sc. second year Chemistry) covers the Halogenation of alkanes which is the substitution reaction of halide group yielding halogen acids. The order of reactivity of all halogens is discussed with alkanes both in bright sunlight and in diffused sunlight. Substitution in higher alkanes yields primary, secondary and tertiary groups separately in different proportions. The Chlorination of methane is discussed in detail with the mechanism that follows including the initiation, propagation and termination steps. The products at various steps yield chloroform and tetra chloromethane. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.