Which one of the following is considered as a compound?

The correct answer is Calcium carbonate.

Key Points

• Calcium carbonate (CaCO₃) is classified as a compound because it consists of chemically bonded elements—calcium (Ca), carbon (C), and oxygen (O).
• A compound is defined as a substance made up of two or more elements chemically combined in a fixed ratio.
• Calcium carbonate is widely found in nature in materials such as limestone, marble, and chalk.
• It has diverse applications, including its use in construction materials, industrial fillers, and as an ingredient in antacids.
• Unlike mixtures (e.g., sugar solution), compounds have uniform chemical properties and cannot be separated by physical means.

Additional Information

• Compound:
  • A compound is a pure substance formed by the chemical combination of two or more elements in fixed proportions.
  • Compounds exhibit unique properties different from the individual elements that compose them.
  • Examples include water (H₂O), sodium chloride (NaCl), and carbon dioxide (CO₂).
• Calcium Carbonate in Nature:
  • Calcium carbonate is abundant in nature, forming essential geological structures such as limestone caves and coral reefs.
  • It also plays a role in the carbon cycle, interacting with atmospheric CO₂ during weathering processes.
• Difference Between Compound and Mixture:
  • Compounds are chemically bonded substances, while mixtures are physical combinations of substances.
  • Mixtures can be separated by physical methods (e.g., filtration), whereas compounds require chemical reactions for separation.
• Applications of Calcium Carbonate:
  • Used as a dietary calcium supplement and antacid in the pharmaceutical industry.
  • Serves as a filler in paper, plastics, and paints, enhancing product quality and durability.
  • Widely utilized in agriculture to neutralize acidic soils and improve fertility.