Calcium sulphate dihydrate is the chemical name of:

Correct option is A

The correct answer is (A) Gypsum.

·         Calcium sulphate dihydrate (CaSO₄·2H₂O) is the chemical name for gypsum, a naturally occurring mineral widely used in construction and other industries.

·         Properties: Soft mineral, easily ground into powder.

·         Uses: Used in cement, fertilizers, and as a soil conditioner. It is also the precursor for making plaster of Paris.

Explanation of Options:

• Washing Soda:
• Chemical Formula: Na₂CO₃·10H₂O (Sodium carbonate decahydrate).
• Not related to calcium sulfate.
• Plaster of Paris:
• Chemical Formula: CaSO₄·0.5H₂O (Calcium sulfate hemihydrate).
• It is made by heating gypsum to about 150°C, driving off some of the water content.
• Baking Powder:
• Chemical Formula: Primarily contains NaHCO₃ (Sodium bicarbonate).
• Used as a leavening agent in baking, unrelated to calcium sulfate.