The dissolution of NaOH in water is not a chemical reaction, but a physical change. According to relevant public information, there are two processes by which solid sodium hydroxide dissolves in water. One is the dissolution process, the process in which Na+ and OH- diffuse into water under the influence of water molecules. This process requires the absorption of heat. Another process is the process of combining sodium ions and water molecules to form hydrated ions, which can be expressed as [Na(H2O)m]+. This process releases heat. Since the heat released by the formation of hydrated ions is greater than the heat absorbed by the dissolution process, the temperature of solid sodium hydroxide will increase as it dissolves in water.
Sodium hydroxide is soluble in water, but does not react with water.
Sodium hydroxide, also knownou known as caustic soda, caustic soda, refractory soda and caustic soda, is an inorganic compound with a chemical formula of NaOH and a relative molecular weight of 39.9970. Sodium hydroxide is highly alkaline and highly corrosive. It can be used as acid neutralizer, masking agent, precipitant, precipitation masking agent, color developer, saponification agent, peeling agent, detergent, etc.
The main reason sodium hydroxide dissolves in water is because it reacts with water to form a sodium hydroxide solution.
In water, the crystal structure of sodium hydroxide will be destroyed and the sodium ions and hydroxide ions will dissociate from the water molecules to form ions in the solution.
Water molecules are polar molecules, with their oxygen atoms carrying a partial negative charge and their hydrogen atoms carrying a partial positive charge. When sodium hydroxide is dissolved in water, the sodium ions will form ionization bonds with the oxygen atoms of the water molecules, and the hydroxide ions will form hydrogen bonds with the hydrogen atoms of the molecules of water.
This ionization reaction and the formation of hydrogen bonds causes sodium hydroxide molecules to dissociate into ions in water. There are a large number of Na+ and OH- ions in the solution, and these ions are uniformly distributed in the water. aqueous solution.
This uniform distribution of ions makes the solution alkaline and sodium hydroxide solutions are corrosive and alkaline.
History of sodium hydroxide
The history of sodium hydroxide (NaOH) dates back to ancient civilizations. Methods for producing alkaline substances have been found in ancient Egyptian and Babylonian ruins, and these alkaline substances are probablysodium hydroxide.
However, the preparation and understanding of true sodium hydroxide dates back to the 17th century. In 1603, German chemist Johann Rudolf Grau had discovered a way to produce an alkaline substance. He boiled wood ash and water, then evaporated the solution to dryness to obtain a solid alkaline substance, which is sodium hydroxide.
In the 18th century, French chemist Nicolas Leblanc and Scottish chemist Daniel Lebanon independently discovered that sodium hydroxide could be produced by electrolysis of brine. This method was widely used and became the main means of preparing sodium hydroxide in industry.