Distillation of ethanol will only produce about 95% ethanol. The mixture of ethanol and water produce what is known as an azeotrope. Azeotropes are a mixture of at least two
different liquids. Their mixture can either have a higher boiling point
than either of the components or they can have a lower boiling point. Azeotropes occur when fraction of the liquids cannot be altered by distillation.
Here's an interesting youtube video explaining this. How to make 100% Ethanol (anhydrous)
Here's an interesting youtube video explaining this. How to make 100% Ethanol (anhydrous)