CaO(aq) does not exist. Explain why not.

Answer 1

CaO(aq) does not exist because CaO is a solid, not a liquid or a gas. The "(aq)" notation is used to indicate that a substance is dissolved in water to form an aqueous solution. However, CaO is insoluble in water, meaning that it does not dissolve in water and does not form an aqueous solution. Instead, it reacts with water to form Ca(OH)2, a solid compound also known as slaked lime, which is able to form an aqueous solution. Therefore, the correct notation for the reaction between CaO and water is CaO(s) + H2O(l) → Ca(OH)2(s).