Mention any three methods of preparation of haloalkanes from alcohols.

1.	Mention any three methods of preparation of haloalkanes from alcohols.
Answer» SOLUTION :Haloalkanes are prepared from alcohols by treating with (i) HCl(ii) `PCl_5` (iii) `SO_2Cl_2` (i) Reaction of alcohol with hydrogen halide: `underset("Ethanol")(CH_3-CH_2OH + HCl) underset(ZnCl_2)OVERSET("ANHYDROUS")to underset("CHLORO ethane")(CH_3 - CH_2 Cl) + H_2O` (ii) Reaction of alcohol with phosphorous halide: `underset("Ethanol")(CH_3-CH_2OH)+underset("Pentachloride")underset("Phosphorus")(PCl_5) to underset("Chloro ethane")(CH_3 - CH_2Cl) + POCl_3 + HCl` (iii) Reaction of alcohol with thionyl chloride: `underset("Ethanol")(CH_3-CH_2OH) + SOCl_2 to underset("Chloroethane")(CH_3-CH_2Cl + SO_2uarr) + HCluarr`

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