How do acidic and basic oxides react with water?

Acidic oxides react with water to form acids, while basic oxides react with water to form bases.

Acidic oxides, also known as acid anhydrides, are oxides of non-metals. When they react with water, they form their corresponding acids. For instance, sulphur trioxide (SO3) is an acidic oxide. When it reacts with water (H2O), it forms sulphuric acid (H2SO4). This can be represented by the equation: SO3 + H2O → H2SO4. This reaction is exothermic, meaning it releases heat. The resulting acids are usually strong acids, which means they fully ionise in water.

On the other hand, basic oxides, also known as base anhydrides, are oxides of metals. When they react with water, they form their corresponding bases. For example, sodium oxide (Na2O) is a basic oxide. When it reacts with water, it forms sodium hydroxide (NaOH). This can be represented by the equation: Na2O + H2O → 2NaOH. This reaction is also exothermic. The resulting bases are usually strong bases, which means they also fully ionise in water.

It's important to note that not all oxides react with water. Some oxides, such as aluminium oxide (Al2O3) and zinc oxide (ZnO), are amphoteric, meaning they can behave as both acidic and basic oxides. They can react with both acids and bases to form salts and water. For example, aluminium oxide reacts with hydrochloric acid (a strong acid) to form aluminium chloride (a salt) and water. It can also react with sodium hydroxide (a strong base) to form sodium aluminate (a salt) and water.

In summary, the reaction of oxides with water is a fundamental concept in chemistry. It helps us understand the behaviour of different substances in aqueous solutions and the nature of acids and bases.