How to separate alcohol and water
Alcohol and water mix instantly! But how can you split them in a flash?
Warning! Only under adult supervision.
- glass bottle with cap;
- isopropyl alcohol;
- sodium chloride (salt);
- food coloring.
Mix some isopropyl alcohol and water in a bottle to create a homogeneous liquid. Add salt and food coloring and shake the mixture well – the liquid readily separates into alcohol and water, and the water is tinted more vividly than the alcohol.
Alcohol and water will mix with each other in any ratio. Sodium chloride dissolves well in water, but poorly in alcohol. When salt is added to the prepared solution, it attracts water molecules to itself, “distracting” them from the alcohol molecules. As a result, when the mixture is shaken, the alcohol molecules separate from the water to form a second layer of liquid. Since water is more dense than alcohol, the water winds up at the bottom. The water is also tinted more vividly because food coloring, like salt, dissolves better in water.
More entertaining experiments await you in the MEL Physics subscription!