Magnesium hydroxide heating

Magnesium hydroxide is heated to produce magnesium oxide and water. Magnesium oxide and water will not react to form magnesium hydroxide. Calcium hydroxide cannot be produced by heating, and calcium hydroxide is not required to be precipitated by heating lime water. Calcium hydroxide is an alkali, a pure substance, not a liquid! Lime water is an aqueous solution of calcium hydroxide and a mixture.