In order to separate a mixture of alcohol (ethanol) and water, use a process known as fractional distillation. This technique relies on the principle that the compounds in the mixture have different boiling points. Since ethanol boils at a lower temperature (78.5 degrees C) than water, the alcohol vaporizes while the water remains a liquid. At some point, it will become an azeotropic mixture where the vapor has the same composition as the liquid. A good distillation column will produce an azeotropic mixture of 95 percent alcohol and 5 percent water. This ratio represents the most pure form of ethanol possible with distillation and is widely accepted as an industry standard.
- Bunsen burner
- Round-bottom flask
- Distillate-capturing flask
- Fractionating column
- Condenser (such as Liebig condenser)
- Thermometer
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Instructions
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1
Pour the ethanol/water mixture into the round-bottom flask.
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2
Assemble the fractional distillation apparatus by attaching the fractioning column to the round-bottom flask. Attach the condenser to the fractioning column and place the distillate-capturing flask under it to capture the distillate.
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3
Place the Bunsen burner below the round-bottom flask and heat the mixture to above the boiling point of ethanol (maintain around 80 degrees C).
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4
Maintain the mixture at a constant temperature until the boiling has ceased. At this point, you have reached the azeotropic point and completed distillation.