An azeotrope is a mixture of two or more liquids in such a ratio that its composition cannot be changed by simple distillation. This occurs because, when an azeotrope is boiled, the resulting vapor has the same ratio of constituents as the original mixture. Because their composition is unchanged by distillation, azeotropes are also called constant boiling mixtures. Common drying agenets for organic compounds : Alcohols : Anhydrous K2CO3, CaSO4 or Mg2SO4 and CaO Alkylhalides/aryl halides : Anhydrous CaCl2,CaSO4 or Mg2SO4 and phosphoric acid Saturated aromatic hydrocarbonds : CaCl2,CaSO4 and phosphoric oxide Aldehydes : CaSO4,Mg2SO4 Na2SO4 Ketones : CaSO4,MgSO4 ,NaSO4 or K2CO3 Organic bases : Solid KOH/NaOH ,CaO or Barium oxide Organic acids : Calcium sulphate, Mg2SO4 Solution An azeotrope is a mixture of two or more liquids in such a ratio that its composition cannot be changed by simple distillation. This occurs because, when an azeotrope is boiled, the resulting vapor has the same ratio of constituents as the original mixture. Because their composition is unchanged by distillation, azeotropes are also called constant boiling mixtures. Common drying agenets for organic compounds : Alcohols : Anhydrous K2CO3, CaSO4 or Mg2SO4 and CaO Alkylhalides/aryl halides : Anhydrous CaCl2,CaSO4 or Mg2SO4 and phosphoric acid Saturated aromatic hydrocarbonds : CaCl2,CaSO4 and phosphoric oxide Aldehydes : CaSO4,Mg2SO4 Na2SO4 Ketones : CaSO4,MgSO4 ,NaSO4 or K2CO3 Organic bases : Solid KOH/NaOH ,CaO or Barium oxide Organic acids : Calcium sulphate, Mg2SO4.