MCQ Detailed View

Limestone is one of the most abundant and important sedimentary rocks on Earth. Chemically, pure limestone is composed of Calcium Carbonate (CaCO₃). This compound occurs naturally in the form of calcite and aragonite minerals, which are two different crystal structures of calcium carbonate.

Calcium carbonate makes up about 95% of pure limestone, giving it a white to gray appearance. The rock is formed over millions of years from the accumulation of shells, coral, algae, and other marine organisms rich in calcium carbonate. When these materials settle and undergo pressure, they gradually harden into limestone.

Pure limestone is highly significant both in chemistry and industry. Some of its key uses include:

1. 
   

   Construction Material – It is widely used as a raw material in cement, concrete, and road-building industries.

   
   


2. 
   

   Agriculture – Finely ground limestone is used to neutralize acidic soils because calcium carbonate acts as a natural base.

   
   


3. 
   

   Glass and Steel Industry – It serves as a flux material, helping to remove impurities during the production process.

   
   


4. 
   

   Chemical Industry – Calcium carbonate is used in the preparation of lime (CaO) and slaked lime (Ca(OH)₂), which have numerous applications.

   
   

From a scientific perspective, pure limestone is a perfect example of how geology and chemistry are interconnected. The mineral composition (CaCO₃) not only defines its chemical identity but also explains its behavior in reactions. For example, when heated strongly, calcium carbonate decomposes into calcium oxide (CaO), also called quicklime, and releases carbon dioxide (CO₂) gas. This reaction is of major industrial importance in cement production.

In conclusion, the chemical name of pure limestone is Calcium Carbonate (CaCO₃). Its versatility, abundance, and wide industrial applications make it one of the most useful natural resources. Therefore, this question rightly falls under the Chemistry MCQs category.