1. Structure: The salt is pure sodium chloride. The chemical formula of sodium chloride is NaCl, and the formula is 58.44, which is composed of chloride ion and sodium ion. In addition to sodium chloride, the industrial salt also contains sodium nitrite exceeding the standard, the chemical formula is NaNO2, and the formula is 69.00, which is composed of nitrite ions and sodium ions.

2. Properties: The salt is relatively stable and the aqueous solution is neutral. Sodium nitrite is relatively stable under dry conditions, but can slowly absorb oxygen and oxidize to sodium nitrate, and the aqueous solution is alkaline.

3. Appearance: Both are white. In special cases, the salt may also be yellow or light blue, and sodium nitrite may also be slightly yellowish. Both are crystalline, and there are certain differences in the geometry under the microscope, but they are indistinguishable from the naked eye.

4. Solubility: Sodium nitrite and salt are very soluble in water, easy to deliquesce, and have no odor.

5. Taste: Sodium nitrite is slightly salty, salty and salty is heavy, and it is difficult to distinguish by taste when eating.