When a metallic oxide dissolves in water, it undergoes a hydrolysis reaction, which means it reacts with water to form new compounds. The specific products and the nature of the solution depend on the metal involved. Here's a breakdown:

1. Basic Oxides:

* Reaction: Basic oxides like sodium oxide (Na₂O) and calcium oxide (CaO) react with water to form metal hydroxides, which are basic in nature.

* Example:

* Na₂O + H₂O → 2NaOH (sodium hydroxide)

* CaO + H₂O → Ca(OH)₂ (calcium hydroxide)

* Solution: The solution becomes basic (alkaline), with a pH greater than 7.

2. Acidic Oxides:

* Reaction: Acidic oxides like sulfur trioxide (SO₃) and phosphorus pentoxide (P₂O₅) react with water to form acids.

* Example:

* SO₃ + H₂O → H₂SO₄ (sulfuric acid)

* P₂O₅ + 3H₂O → 2H₃PO₄ (phosphoric acid)

* Solution: The solution becomes acidic, with a pH less than 7.

3. Amphoteric Oxides:

* Reaction: Amphoteric oxides like aluminum oxide (Al₂O₃) and zinc oxide (ZnO) can react with both acids and bases.

* Example:

* Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O (reaction with acid)

* Al₂O₃ + 2NaOH + 3H₂O → 2Na[Al(OH)₄] (reaction with base)

* Solution: The solution can be acidic, basic, or neutral depending on the conditions.

4. Other Factors:

* Solubility: Not all metallic oxides are soluble in water. Some, like iron oxide (Fe₂O₃) are essentially insoluble.

* Temperature: The solubility of most metallic oxides increases with temperature.

* pH: The pH of the solution can influence the solubility of certain metallic oxides.

In summary:

The reaction of a metallic oxide with water depends on the nature of the metal. Basic oxides form hydroxides, acidic oxides form acids, and amphoteric oxides can react with both. The solubility and other factors also play a role in the overall reaction.