Sodium carbonate is a salt composed of carbonate ions and sodium ions. In chemistry, "salt" is a compound composed of acid radical and metal ion. Acid radical is a radical which contains sulfate radical, hydrochloride radical, carbonate plasma and their complex ions, while metal ions are formed by hydrolysis of metals in a complex state. Together, they are called "salt".

Sodium carbonate, commonly known as soda ash, caustic soda, soda ash and caustic soda washing, is a strong electrolyte with universality of salt. Sodium carbonate is one of the important chemical raw materials, which is widely used in light industry, daily chemicals, building materials, chemicals, food, metallurgy, textiles, petroleum, national defense, medicine and other fields.

Definition of alkali: All anions ionized in aqueous solution are hydroxide ions (all substances that can absorb protons during ionization are alkaline, and all anions are OH- are bases, collectively referred to as alkali), which react with acids to form salts and water. Typical alkali such as amine (including ammonia, chemical formula: NH3·H2O), caustic soda, hydrated lime, etc.

Alkalinity of sodium carbonate: when sodium carbonate is hydrolyzed in aqueous solution, ionized carbonate ions combine with hydrogen ions in water to form bicarbonate ions, which leads to the decrease of hydrogen ions in the solution and the increase of ionized hydroxide ions, so the pH value of the solution is alkaline.

Solid at room temperature, white powder, easily soluble in water. Edible noodles are stable, but will decompose at high temperature to produce sodium oxide and carbon dioxide. Long-term exposure to the air can absorb moisture and carbon dioxide in the air, generate sodium bicarbonate and form lumps. They are highly hygroscopic and easy to agglomerate.