Why magnesium hydroxide is alkaline

Magnesium hydroxide is a kind of medium strong alkali. The solubility of magnesium hydroxide is relatively small. The solubility of magnesium hydroxide in water is only 1.2mg/100ml, but all the parts of magnesium hydroxide dissolved in water are ionized, producing Mg2 + (50%), oh - (8%) (and [MgO2] 2 - (or writing [Mg (OH) 4] 2 -) and [MGO3] 4 - (or writing [Mg (OH) 6] 4 -) (42%).


Magnesium hydroxide is a white crystal. The specific gravity of magnesium hydroxide is 2.36. Magnesium hydroxide is insoluble in water and alcohol. Magnesium hydroxide can be soluble in acid and ammonium salt solution. The refractive index of magnesium hydroxide is 1.580. Magnesium hydroxide can decompose to form magnesium oxide and water, and the reaction will absorb heat with the heat capacity of 10.7 kcal / mol. magnesium hydroxide will decompose at 340 ℃. When the temperature reaches 430 ℃, the decomposition speed is the fastest. When the temperature reaches 490 ℃, the decomposition of magnesium hydroxide ends.