Why Can't Salt Be Separated from Water Using a Centrifuge or by Letting It Sit?

[tony873004]

Why can’t I separate salt from water with a centrifuge, or simply by letting it sit for some time? Salt water is a homogeneous mixture, not a compound. So the salt and the water are not chemically bonded. Why don’t the denser NaCl molecules sink to the bottom of the H₂0 molecules?

 

[Borek]

NaCl are not in form of molecules, they are dissociated (not that it answers your question).

Notion of density doesn't make much sense for a single molecule. Even if it was making sense, effects of molecular collisions (due to thermal motion of molecules) are orders of magnitude higher that effects of gravity.

 

[tony873004]

Thanks Borek!

 

[sankalpmittal]

Salt and water are homogeneous solutions , yes and NaCl can easily dissolve in water because of its low electrostatic single bond force .

Water easily dissolves it . It is a true solution cannot be seen , cannot be collected through permeable membrane or filter paper .

No matter of centrifugal force , it cannot be separated .

 

[LudusRex]

While it is true that salt water is a homogeneous mixture and the salt and water are not chemically bonded, separating salt from water is not as simple as using a centrifuge or allowing it to sit for some time. This is because the molecules in a homogeneous mixture are evenly distributed throughout the mixture and do not settle out based on density. In order to separate the salt from water, a physical process such as evaporation or distillation must be used, which takes advantage of the different boiling points of salt and water. A centrifuge would not be effective in separating the two substances as they do not have different densities. Additionally, simply allowing the mixture to sit would not result in separation as the molecules would remain evenly distributed.