Is magnesium hydroxide a strong base?

No, magnesium hydroxide is a medium strong base.


The pH of a chemical substance is relative, which is determined by the degree of ionization in its aqueous solution.


The more active the metal is, the greater the degree of ionization in the water, and the stronger the acidity and alkalinity. Because of the degree of ionization in the water, magnesium hydroxide can only belong to medium strong alkali (magnesium hydroxide has a very small solubility, and the solution is very alkaline, sometimes treated as a weak alkali). When heated to 623k (350 ℃), it is dehydrated and decomposed: Mg (OH) 2 → mgo+h2o, which is easily soluble in acid or ammonium salt solution.


Like magnesium oxide, it is easy to absorb carbon dioxide in the air and gradually form basic carbonate composed of 5mgo · 4co2 · xH2O. When the temperature is higher than 350 ℃, it is decomposed into magnesium oxide and water, but it can be completely dehydrated only when the temperature is higher than 1800 ℃.


Magnesium hydroxide is an excellent flame retardant for plastic and rubber products. As flue gas desulfurizer in environmental protection, it can replace caustic soda and lime as neutralizer of acid containing wastewater. It is also used as oil additive to prevent corrosion and desulfuration. In addition, it can also be used in the refining of electronic industry, medicine and granulated sugar, as thermal insulation materials and manufacturing other magnesium salt products.


Magnesium hydroxide has excellent buffer performance, reaction activity, adsorption capacity and thermal decomposition performance. It can not only be used as chemical materials and intermediates, but also as a green flame retardant and additive for rubber, plastic, fiber, resin and other polymer material industries. Magnesium hydroxide is mainly used as flame retardant, acid wastewater treatment agent, heavy metal removal agent and flue gas desulfurization agent in the field of environmental protection.