Question

Which one of the following materials contains
calcium ?
(a) China clay (b) Corundum
(c) Gypsum
(d) Talc​

Answer 1

C. Gypsum contains calcium

Explanation:

• Gypsum, chemically calcium sulphate dihydrate is a calcium compound.
• It has about 29.4 percent calcium in the anhydrite form and about 23.3 percent in the hydrous form.
• Gypsum which is added as a fertilizer contains about 22% calcium which is readily available in the soluble form for the plants to absorb easily.  

1. China clay is a made up of kaolinite and is a hydrous aluminosilicate compound
2. Corundum consists of aluminium oxide.
3. Talc is a type of clay mineral formed with hydrated magnesium silicate

Answer 2

Gypsum (CaSO4. 2H2O ) contain calcium in it.

Option (C) is correct.

Explanation:

• Gypsum contains calcium in it.
• Gypsum is an inorganic compound with the chemical formula CaSO4.2H2O
• Gypsum is an anhydrous compound and contains 2 molecules of water in it. The blue color of calcium sulfate is due to the presence of water molecules in it.
• Gypsum is used as a fertilizer in the soils for plant growth.
• Gypsum is also used in making chalks, plasters boards, etc.