Can be distinguished based on the amount of gas produced by the reaction.
1. Reaction of sodium carbonate and hydrochloric acid
1) Chemical reaction equation
Na2CO3+HCl=NaHCO3+NaCl, NaHCO3+HCl=NaCl+H2O+CO2 ↑ ?
2) Test phenomenon: When dilute hydrochloric acid is added dropwise to sodium carbonate powder, no bubbles will appear at first. As the amount added increases, gas begins to be released.
3) Explanation: Sodium carbonate first reacts with hydrochloric acid to form sodium chloride and sodium bicarbonate. After all is converted into sodium bicarbonate, the generated sodium bicarbonate reacts with more hydrochloric acid to form chlorine. Sodium and water and carbon dioxide. ? Heating will accelerate the evolution of gas.
2. Reaction of sodium bicarbonate and hydrochloric acid
1) Chemical reaction equation
NaHCO3+HCl=NaCl+H2O+CO2↑
2) Test phenomenon: The reaction between NaHCO3 and dilute hydrochloric acid is much more violent than the reaction between Na2CO3 and dilute hydrochloric acid, directly generating a large amount of gas (CO2)
Extended information
1. Carbonic acid Sodium
Sodium carbonate [497-19-8] (Na2CO3), molecular weight 105.99. The purity of chemicals is mostly above 99.5% (mass fraction). It is also called soda ash, but it is classified as salt, not alkali. Also known as soda or soda ash in international trade. It is an important organic chemical raw material and is mainly used in the production of flat glass, glass products and ceramic glazes. It is also widely used in daily washing, acid neutralization and food processing.
Before the artificial synthesis of soda ash, it was discovered in ancient times that the ashes burned after drying certain seaweeds contained alkali. After leaching with hot water and filtering, brown alkali solution could be obtained for washing. A large amount of trona comes from minerals, mainly buried underground or alkaline lakes. Trona minerals that exist in sedimentary layers have the highest grade and are widely distributed.
The earliest invention of the method of artificially synthesizing soda ash was at the end of the 18th century. France's Lou Blanc used Glauber's salt, limestone and coal to reduce and carbonate it at high temperatures to obtain a crude product - black ash, mainly containing Na2CO3. After leaching, evaporation, refining, recrystallization and drying, heavy soda ash with a purity of approximately 97% is obtained. In 1861, Belgian E. Solvay independently invented and obtained a patent. Because the protection of technical secrets has not been widely used, it was not until the 1920s that a breakthrough came from the United States. In particular, the famous Chinese chemical expert Hou Debang published the book "Soda Ash Manufacturing" in 1932, which will be kept secret for 70 years. Solvay Law announced In the world. Hou Debang also created Hou's alkali production method from 1939 to 1942 and established a pilot workshop in Sichuan. In 1952, a joint alkali production workshop was established in Dalian Chemical Plant. The NA method introduced by Japan's Asahi Glass Co., Ltd. is essentially a compromise method between joint alkali and ammonia-alkali. The ratio of soda ash and ammonium chloride can be adjusted at will.
2. Sodium bicarbonate
Sodium bicarbonate, chemical formula NaHCO?, commonly known as baking soda. White fine crystals, less soluble in water than sodium carbonate. It is also an industrial chemical. The solid begins to decompose gradually above 50℃ to form sodium carbonate, carbon dioxide and water, and completely decomposes at 270℃. Sodium bicarbonate is an acid salt formed after the neutralization of a strong base and a weak acid. It is weakly alkaline when dissolved in water. This property allows it to be used as a leavening agent in food preparation. After sodium bicarbonate is used, sodium carbonate will remain. If used too much, the finished product will have an alkaline smell.
Sodium bicarbonate is white crystal, or opaque monoclinic fine crystal. Specific gravity 2.15. Odorless, non-toxic, salty in taste, soluble in water and slightly soluble in ethanol. It is soluble in 10 parts of water at 25℃ and 12 parts of water at about 18℃. Its aqueous solution is slightly alkaline due to hydrolysis. It is stable at room temperature and easily decomposes when heated. It gradually decomposes above 50°C and completely loses carbon dioxide at 270°C. It has no change in dry air and slowly deliquesces in humid air.
Baidu Encyclopedia-Sodium Carbonate, Baidu Encyclopedia-Sodium Bicarbonate