Limestone, chalk and marble are different forms of-

Correct option is C

The correct answer is (c) Calcium carbonate.
· Limestone, chalk, and marble are different forms of calcium carbonate (CaCO₃). Although they have the same chemical composition, they differ in terms of their crystalline structure and formation process:
· Limestone: Formed from sedimentation and is a common rock used in construction.
· Chalk: A softer, porous form of calcium carbonate, often used in classrooms.
· Marble: A metamorphic form of limestone, which becomes denser and harder under high pressure and temperature.
Information Booster:
· Sodium hydroxide (NaOH): Commonly known as lye or caustic soda, used in cleaning products.
· Ammonium hydroxide (NH₄OH): A solution of ammonia in water, used as a cleaning agent.
· Calcium hydroxide (Ca(OH)₂): Also known as slaked lime, used in various industrial processes.