why is mg oxide alkali?
Answers
Answer:
Is MgO an alkali?
Is MgO an alkali?Alkalis are soluble bases. An alkaline solution can be formed when a metal oxide is dissolved in water. An acidic solution can be formed when a non-metal oxide is dissolved in water. For example, magnesium oxide dissolves to form alkaline solutions.
Answer:
, dr: Chemists would generally say "No". But it's not as cut and dried as one might think. The alkaline character of magnesia and heavier Group 2 oxides is one of many examples in chemistry where the actual character is intermediate between the extremes a yes/no answer seems to imply.
Usually the term "alkali" is reserved for the hydroxides of Group 1 metals, which (at least among compounds of commonly observed elements) uniquely combine strong basic character with high solubility in water. Even barium hydroxide, whose solubility in water is limited to less than one molar unless the water is heated, does not get there on solubility.
That being said, there are applications where magnesia (and its congeners with heavier alkaline earth metals, such as lime) functions as an alkali would. Given the solubility product of magnesium hydroxide being roughly 10−11 (different sources quote slightly different values), magnesium remains freely soluble up to a pH of about 9 (with lime the corresponding limit for calcium is around pH 11 or 12), which is high enough to displace most transition metal hydroxides from solution.