Passing Carbon Dioxide through Slaked Lime

When carbon dioxide is passed through slaked lime, a chemical reaction takes place:

Ca(OH)2 + CO2 -> CaCO3 + H2O

This reaction results in the formation of calcium carbonate and water. Calcium carbonate is a white, powdery substance that is commonly used as a filler in the production of plastics, paints, and coatings.

Explanation of the Reaction

The reaction between slaked lime (calcium hydroxide) and carbon dioxide is an example of a double displacement reaction. This type of reaction involves the exchange of ions between two compounds.

In this case, the calcium ion (Ca2+) in the slaked lime reacts with the carbonate ion (CO32-) in the carbon dioxide to form calcium carbonate (CaCO3). At the same time, the hydroxide ion (OH-) in the slaked lime reacts with the hydrogen ion (H+) in the carbonic acid (H2CO3) that is formed when carbon dioxide dissolves in water. This produces water (H2O) and completes the reaction.

Uses of Calcium Carbonate

Calcium carbonate has a wide range of uses, including:

1. As a filler in the production of plastics, paints, and coatings.

2. As a dietary supplement for people who need more calcium in their diet.

3. As an antacid to relieve heartburn and indigestion.

4. In the production of cement, concrete, and other building materials.

5. In the purification of iron from iron ore in the steel industry.