Question

Hi, so I have a lab to distillate n-hexane ( BP : 68 C) and toulen ( 110C)

So, I have 3 temperature range : 75 , 85 , 100. Why do I also receive toulen ( 10% ) while the boil degree is 75C ? , I thought it need to reach 110 for toluen to evaporte

(PS: It can be a fault of mine in lab procedure, for example, 75 is 75% of maximum heat instead of 75 degree. )

Edit: the lab is about boiling in a Hickman still, allowing evaporate liquid to again condense in difference layer )

Answer 1

Hi it's not your fault. The theory behind this composition is Azeotropic mixture. A liquid mixture of two or more substances that retains the same composition in the vapor state as in the liquid state when distilled or partially evaporated under a certain pressure is an azeotrope. In such a case it is not possible to separate the components by fractional distillation.

Hope this helped you!

Thank You So Much! Please Rate this answer as you wish.("Thumbs Up")