Why doesn't Salt Water Freeze?

Adding salt to water disrupts the equilibrium of water reducing the freezing point. As ice forms the left over water becomes more saturated with salt, until the water becomes super saturated, which occurs at -21.1 degrees C. At this point the salt begins to crystallize out of solution and the water (no longer salty) will freeze. You can find more information here: http://www.worsleyschool.net/science/fil...