PCl5 on reaction with alcohol and carboxylic acid, replace −OH group with −Cl. ROH+PCl5⟶RClRCOOH+PCl5⟶++POCl3+HClRCOCl2POCl3+HCl Related Theory PCl5 is used as a chlorinating agent and dehydrating agent for the synthesis of pesticides, phosphite antioxidants, plasticizers and stabilizers for plastic and elastomers etc