Soda is a transliteration of SODA, and its chemical formula is Na2CO3. It has many names, the scientific name is sodium carbonate, and the common name is soda, also known as soda ash or baking soda powder. There are three kinds of sodium carbonate hydrate with crystal water: sodium carbonate monohydrate (Na2CO3·H2O), sodium carbonate heptahydrate (Na2CO3·7H2O) and sodium carbonate decahydrate (Na2CO310H2O). Sodium carbonate decahydrate is also called washing soda, washing alkali or crystal alkali.

Anhydrous sodium carbonate is white powder or fine particles, easily soluble in water, and its aqueous solution is alkaline. It has a strong hygroscopicity and can absorb water in the air to form a hard block. Sodium carbonate decahydrate is a colorless crystal. If it is placed in the air at room temperature, it will lose its crystal water and become sodium carbonate monohydrate. Both sodium carbonate decahydrate and sodium carbonate monohydrate will become anhydrous sodium carbonate when heated. Sodium carbonate is very stable and is not easy to decompose when heated. Carbon dioxide can be released in case of acid;

Na2CO3+2HCl====2NaCl+H2O+CO2↑?

Sodium carbonate solution can also absorb carbon dioxide to form sodium bicarbonate;

Na2CO3+H2O+CO2====2NaHCO3

Among the three sodas, sodium carbonate is the most widely used. It is a very important chemical product and an important raw material for glass, soap, textile, paper making, leather making and other industries. It is also used in metallurgical industry and purified water. It can also be used for the manufacture of other sodium compounds. As early as the eighteenth century, it was listed as one of the basic chemical raw materials-three acids and two alkalis along with sulfuric acid, hydrochloric acid, nitric acid and caustic soda. In daily life, soda also has many uses. For example, it can be directly used as a detergent. Adding some soda when steaming steamed bread can neutralize the acidic substances produced in the fermentation process.