Why put salt on the snow?

After salt is dissolved in water, its freezing point is-10℃. In addition to absorbing heat, the freezing point of salt water is low, so it is difficult to form ice cubes after salt is dissolved in snow water. In fact, snow is constantly melting and solidifying, but the speed of the two is equal, so it has always remained solid. Because the freezing point of salt water is lower than that of water, the water around the snow becomes salt water and cannot be solidified, so the snow will continue to melt and cannot be solidified, so it will be less and less. Because salt water will corrode roads, many countries have not allowed to use salt to melt snow, but use snow melting agent to melt snow. Another theory is based on pure chemical theory. This should start with the chemical composition of salt. The composition of salt is sodium chloride and the composition of snow is water. Sodium chloride is a chemical substance that is very soluble in water. When sodium chloride is dissolved in water, sodium chloride aqueous solution is generated, which contains sodium ions and chloride ions. When there are chloride ions and sodium ions in the freezing process, the chloride ions and sodium ions will destroy the crystal network structure of water and make it impossible to freeze water. In other words, sprinkling salt is beneficial to the melting of snow. After being dissolved in water, the ion concentration in water increases, so that the liquid vapor pressure of water decreases, while the solid vapor pressure of ice remains unchanged. In order to reach the solid-liquid vapor pressure state of the ice-water mixture, the ice melted. This principle can also explain why salt water is not easy to freeze. Water is a special substance, that is, the density becomes smaller after freezing (generally, the density is higher in solid state than in liquid state), so the greater the pressure, the lower the melting point of ice. It is often seen that snow melts easily where the wheels run over. After the snow melting agent is sprinkled on the snowy road surface, it is easier to melt the snow after being crushed by vehicles. However, this has two disadvantages. First, the freezing point is limited, and it makes no difference if the weather is too cold. Second, salt is corrosive to roads, and long-term use will damage the pavement.