: How is salt a solid state and water freezes at 0 °C but when you put salt on roads at -10 it stays in liquid state?

Question

So it’s -10 °C where I am today and there are loads of puddles on the pavements and roads because they have been salted (I’m aware that the ground temperature might be higher than -10). But I can’t wrap my mind around the fact that above 0 °C salt can be solid but when it’s diluted into water it lowers the freezing temperature.
But to what temperature? Is there a point where salt is no longer effective on roads and pavements?
Does it depend on the amount of salt mixed with water?
When the sea freezes is it only the H2O that solidifies? What about the salt?
Please, this has kept me up at night!

In: Chemistry

Answer 1

Simple put, the sodium ( Na)-and chloride (Cl) diffuse through the water and prevent the water molecules to organize close together to make ice. It works up until -9 to -15 depending on what type of salt you use… sodium, magnesium ect.