Question

Which of the following is not made of calcium carbonate?

• A. Calcspar
• B. Witherite
• C. Marl
• D. Chalk

Hint:

Materials like chalk, limestone, and marble are composed of calcium carbonate, while Witherite consists of barium carbonate.

Answer 1

The Correct Option is B

Calcium carbonate (CaCO\(_3\)) is a common compound found in many minerals and natural materials. It forms a major component of limestone, chalk, and marble.
Step 1: Understanding the Composition of Each Option - Calcspar (Calcite): A crystalline form of calcium carbonate (CaCO\(_3\)).
- Witherite: Composed of barium carbonate (BaCO\(_3\)), not calcium carbonate.
- Marl: A mixture of clay and calcium carbonate, making it rich in CaCO\(_3\).
- Chalk: A soft, porous form of calcium carbonate (CaCO\(_3\)).


Step 2: Evaluating the Options - Option (A) - Incorrect: Calcspar (Calcite) is composed of CaCO\(_3\).
- Option (B) - Correct: Witherite contains BaCO\(_3\) instead of CaCO\(_3\).
- Option (C) - Incorrect: Marl contains a high proportion of calcium carbonate.
- Option (D) - Incorrect: Chalk is composed of calcium carbonate.


Step 3: Conclusion Since Witherite is composed of barium carbonate (BaCO\(_3\)) instead of calcium carbonate (CaCO\(_3\)), the correct answer is option (B).