The mixture of 50/50 water and ethanol results in a solution that will not fraction - either by gravity or by distillation. It will sit pretty much forever without seperating, and will boil off completely at 73*C (I think) and will not fraction as a condensate. This is known as an "azeotrope," and there are other combinations which will behave in this manner as well. All are uncommon but noteworthy.
(end trivia)
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