Animated Solution for Chemistry - s and p-Block Elements: Which of the following on thermal decomposition yields a basic as well as acidic oxide?

When tackling questions about thermal decomposition and the nature of the resulting products, it is crucial to have a firm grasp on the periodic table trends. The problem asks us to identify a compound that, upon heating, breaks down to yield two distinct oxides: one basic and one acidic.

The fundamental rule of thumb in inorganic chemistry is that metal oxides are generally basic in nature (they react with water to form bases), whereas non-metal oxides are generally acidic (they react with water to form acids). With this logic bridge established, we can systematically evaluate each option.

Let's test the thermal decomposition of the given compounds one by one:

Option (a): Sodium Nitrate When sodium nitrate is heated, it decomposes to give sodium nitrite and oxygen gas. This reaction does not produce two oxides, so we can eliminate it.

Option (b): Potassium Chlorate Heating potassium chlorate yields potassium chloride and oxygen gas. Again, no acidic or basic oxides are formed here.

Option (c): Calcium Carbonate Calcium carbonate undergoes a classic thermal decomposition reaction to form solid calcium oxide and carbon dioxide gas. Let's analyze these products. Calcium is an alkaline earth metal, making calcium oxide ($\text{CaO}$) a basic oxide. Carbon is a non-metal, making carbon dioxide (${\text{CO}}_2$) an acidic oxide. This perfectly satisfies the condition given in the question!

Before we conclude, let's quickly look at the last option to ensure we haven't missed any exceptions.

Option (d): Ammonium Nitrate Ammonium nitrate decomposes into nitrous oxide and water vapor. Both nitrous oxide (${\text{N}}_2\text{O}$) and water (${\text{H}}_2\text{O}$) are neutral oxides. They are neither acidic nor basic.

Therefore, the only compound that yields both a basic and an acidic oxide upon thermal decomposition is calcium carbonate. The correct option is (c).