Why do we use salt to melt ice and snow?

Question

I 'm just wonderin, and if u could give me a scientific reasons, like the chemical reactions and etc.

Answer 1

The addition of any solute to a solution will lower the freezing point and elevate the boiling point. These are called colligative properties.

The salt dissolves in the ice/water at the surface. This makes more water for the rest of the salt to dissolve into. The salt ions change the melting point of the salt/water mixture. The ice should now still be a liquid at a lower temperature so it must melt to change phase and become a liquid with a lower freezing point.

Answer 2

water freezes at 32 farenheit
water + salt freezes at a lower temp

lets imagine the temp was 20 degrees less, 12 farenheit

if it's 20 degrees outside, normal ice would stay ice, but water + salt would not be cold enough to freeze

this is called freezing point depression