The hydroxyl group of an alcohol is replaced by halogen on reactionwith concentrated halogen acids, phosphorus halides or thionyl chloride.Thionyl chloride is preferred because the other two products areescapable gases. And Williamson ether synthetic is name reaction for converting sodium salt of alcohol into the ether by reaction with alkyl halide.Hope it clears. If u have doubts then please clearify. And if u like my answer then please approve answer
