2.1.5. Reaction of Metallic Oxides with Acids

Take a small amount of copper oxide in a beaker and add dilute hydrochloric acid slowly while stirring.

In this step, we are starting an experiment with copper oxide and hydrochloric acid. Copper oxide is a type of metallic oxide. When we add the acid to the copper oxide, it's important to do so slowly and stir the mixture to allow the reaction to occur properly. The method involves observing how the materials mix together and what changes happen during this process.

Think of it like making a smoothie. You add fruit (copper oxide) to milk (hydrochloric acid) slowly and blend (stir) it. You notice how the mixture changes color and texture as you combine them.

Note the colour of the solution. What has happened to the copper oxide?

As you mix the copper oxide with hydrochloric acid, you should observe that the color of the solution changes to blue-green. This color indicates that a reaction is taking place, resulting in the formation of a new compound, copper(II) chloride, dissolved in the solution. The copper oxide actually dissolves in the acid, transforming the initial solid into a liquid.

Imagine adding sugar (copper oxide) to water (hydrochloric acid). At first, the sugar is solid and doesn't mix in. But as you stir, it dissolves and changes the appearance of the water. This is similar to what happens in this chemical reaction.

The general reaction between a metal oxide and an acid can be written as –

Metal oxide + Acid → Salt + Water

This equation summarizes what happens in the reaction between metal oxides and acids. In this case, copper oxide (the metal oxide) reacts with hydrochloric acid to produce copper(II) chloride (the salt) and water. The concept of acids reacting with metal oxides is similar to how bases react with acids. Metal oxides are classified as basic oxides because they exhibit behavior similar to that of bases in their reactions with acids.

Consider baking soda (a base) reacting with vinegar (an acid) to produce carbon dioxide gas, water, and a salt. Just like that, metal oxides also undergo a reaction with acids, producing a salt and water.

Since metallic oxides react with acids to give salts and water, similar to the reaction of a base with an acid, metallic oxides are said to be basic oxides.

Metallic oxides are categorized as basic oxides because they follow the same principles as bases when they react with acids. Their capacity to neutralize acids and produce salt and water during reactions confirms their basic nature. This is a critical feature for understanding how different compounds behave chemically.

Imagine how an antacid (acting as a base) neutralizes stomach acid for relief. Basic oxides do this in a similar way when they interact with acids, helping us understand the broader category of acids and bases.

--