How does salt stop water freezing?

Question

I know it raises the freezing point, but what is going on at the molecular level?

Yes, OK, lowers it.

Now - WHY?

Answer 1

Dissolving any substance in water will lower the freezing point by a factor directly proportional to the amount of the substance dissolved in it. This is because dissolving something in water interferes with the crystalline structure that water forms when it freezes. This phenomenon is called "freezing point depression."
You can read more about it here:
http://members.aol.com/profchm/fpdepres.html
http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/meltpt.html

Answer 2

Salt dissociates into ions (Na+ Cl-) in water. It also releases some heat. By ionizing, it lowers the freezing point of water. It does not stop water from freezing, it just makes it happen at lower temperatures.

Answer 3

It lowers the freezing point, not raises it. It lowers it to below the expected minimum ambient temperature, so the water doesn't freeze. To understand what is going on, you need to research "colligative properties".

Answer 4

You meant that it lowers the freezing point.

Answer 5

Now you are asking a question no one knows the answer to(I think anyway). There are a lot of things that are known but the reason is not known. Thats why we have god-so you can say god made it so.

Answer 6

warm water