Ha| ogenation reactions(卤化反应) heat CH4 X2- CH3x CH2x2+ CHX3 CX4 HX or light XF, CI halomethane dihalomethane trihalomethane tetrahalomethane or br The reaction of an alkane with a halogen is called halogenation. In these reactions a halogen atom replaces one or more of the hydrogen atoms of the alkane. Reactions of this type, in which one atom or group replaces another. are called substituion reactionsHalogenation reactions (卤化反应） CH4 + X2 heat or light CH3X + CH2X2 + CHX3 + CX4 + HX X=F halomethane dihalomethane trihalomethane tetrahalomethane , Cl, or Br The reaction of an alkane with a halogen is called halogenation. In these reactions a halogen atom replaces one or more of the hydrogen atoms of the alkane. Reactions of this type, in which one atom or group replaces another, are called substituion reactions