Question

Why would distillation not be a good method for separating a mixture of hexane and water? Suggest a better way to separate these two liquids (give the name of a specific piece of chemical apparatus).

Answer 1

Hexane and water are immiscible liquids, hence they will not form solution. If we try to separate each by distillation then at around 68^oC hexane will boil and try to evaporate but at the same temprature some part of water will also be evaporated and this will cause contamination in distilate.

And as hexane-water are immiscible we can separate using separating funnel. This method of sepration is simple and easy to use with effective separation. When mixture of hexane and water is added to separating funnel two layers will form. Upper layer is of hexane (0.6548 g/mL) as it has low density then water (1 g/mL) and lower layer will be of water. Lower layer can be removed by simpley opening tab and then stopping as soon as water is removed completly to give two separated liquids.