The headmaster visited the school and said it would be nice if it were a little greener. What does it mean that the school was covered with salt the next day?

The leader of the Education Bureau visited a school, accompanied by the principal. He said to the headmaster, on the whole, it's not bad. It would be better if the playground were greener. The next day, the headmaster had several cars of salt dragged around the playground. (Greening is not sodium chloride)

Sodium chloride is an inorganic ionic compound with the chemical formula of NaCl, which is colorless cubic crystal or fine-grained powder and has a salty taste. The appearance is white crystal, and its source is mainly seawater, which is the main component of salt. Soluble in water and glycerol, slightly soluble in ethanol (alcohol) and liquid ammonia; Insoluble in concentrated hydrochloric acid. Impure sodium chloride deliquesces easily in the air.

Its stability is good and its aqueous solution is neutral. Electrolysis of saturated sodium chloride solution is generally used in industry to produce chemical products such as hydrogen, chlorine and caustic soda (commonly known as chlor-alkali industry). It can also be used for ore smelting (electrolysis of molten sodium chloride crystals to produce active metal sodium), preparation of physiological saline in medical treatment and seasoning in life.

Extended data sodium chloride is a white and odorless crystalline powder. The melting point is 80 1℃ and the boiling point is 1465℃. Slightly soluble in ethanol, propanol and butane, it becomes plasma after being mixed with butane, but it is soluble in water, and its solubility in water is 35.9g (room temperature). NaCl can form colloid when dispersed in alcohol, and its solubility in water is reduced by the presence of hydrogen chloride, and it is almost insoluble in concentrated hydrochloric acid. Odorless, salty and deliquescent. Soluble in water, soluble in glycerol, almost insoluble in ether.

Sodium chloride crystals form stereo symmetry. In its crystal structure, the larger chloride ions are arranged in the cube with the densest packing, and the smaller sodium ions fill the octahedral gaps between chloride ions. Each ion is surrounded by six other ions. This structure also exists in many other compounds, called sodium chloride structure or halite structure.