Why sprinkle salt on snow?

Because it can melt snow

Let’s first take a look at some of the physical and chemical properties of table salt (the main component Nacl) used to melt snow:

① Solubility. Table salt It is easy to dissolve in water, which is a very common physical phenomenon.

② Hygroscopicity. The surface of salt is usually surrounded by a thin film of saturated salt solution. When the vapor of this thin film solution When the pressure is lower than the partial pressure of water vapor in the air, the salt will absorb the moisture in the air and deliquesce; conversely, when it is higher than the partial pressure of water vapor in the air, it will appear dry. Of course, this only occurs when the salt is exposed to the air Phenomenon, salt sealed in a packaging bag and isolated from the surrounding air will not deliquesce;

③The freezing point is low. The freezing point I am talking about here does not actually refer to pure salt (Nacl) crystals The melting point is because it needs to be heated to thousands of degrees Celsius to melt without the participation of water. The freezing point mentioned here refers to the freezing point of the salt solution. Experiments show that if the salt solution contains 20% salt, its freezing point It will drop to -16℃.

Salt has many other properties, but to explain this problem, the above ones are enough:) By the way, the main component of snow is solid water - -Small ice crystals, no matter how low the temperature is, the ice will sublime, so water vapor is diffused around the snow.

When we sprinkle salt on the snow, the salt uses its moisture absorption properties to absorb the snow The water vapor on the surface makes itself more and more "moist", and the thin film of salt solution becomes more and more obvious. I think that at this time, the solution layer is like a spark constantly "invading" the surrounding snow layer, and finally Turning against guests, all the snow was wiped out