Salt refers to a kind of compound in which metal ions or ammonium ions (NH4+) are combined with acidic ions or nonmetallic ions. Such as sodium chloride, calcium nitrate, ferrous sulfate and ammonium acetate, such as calcium sulfate, copper chloride and sodium acetate. Generally speaking, salt is the product of metathesis reaction. Salt reacts with salt to produce new salt and new salt, salt reacts with alkali to produce new salt and new alkali, salt reacts with acid to produce new salt and new acid, such as sulfuric acid and sodium hydroxide to produce sodium sulfate and water, and sodium chloride and silver nitrate to produce silver chloride and sodium nitrate. There are other reactions that can also produce salts, such as displacement reactions. The solution of soluble salt is conductive, because there are free-swimming ions in the solution, so it can be used as electrolyte. Hydrochloric acid is not only an important product of salt chemical industry, but also an important raw material for producing silicon materials. Salt is a kind of crystal.
Salt can be divided into single salt and double salt. Single salt has normal salt, acid salt and alkaline salt, and double salt has double salt and double salt. Among them, acid salts contain hydrogen ions in addition to metal ions and acid ions, and basic salts also contain hydroxide ions in addition to metal ions and acid ions. The compound salt can be dissolved in water, and can generate the same combined salt as the original salt ion. When the double salt is dissolved in water, a double salt complex with complex ions different from the original salt can be formed.
Strong base weak acid salt is a salt produced by the reaction of strong base and weak acid, which is alkaline when dissolved in water, such as sodium carbonate. Strong acid and weak base salt is a salt produced by the reaction of strong acid and weak base, which is acidic when dissolved in water, such as ferric chloride.