You could smell each beaker since water does not have a specific scent while ethanol does
If the contents of the two beakers are distilled, water boils at 100oc and pure water is collected. The other solution will not boil at 100oc, it will boil at a lower temperature and two fractions will be collected after simple distillation.
To safely determine which beaker contains just water, you can use simple distillation. By heating the liquid in each beaker, you can observe the boiling points—pure water boils at 100°C, while the ethanol-water solution will boil at a lower temperature. By collecting and measuring the distillates, you can identify which beaker contains water and which contains the ethanol solution.
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