Question

Limestone is
A. CaO
B. \[{\rm{Ca(OH}}{{\rm{)}}_{\rm{2}}}\]
C. Both A and B
D. None of these

Answer 1

Hint: Limestone is a mineral. It is a rock that is formed due to the sedimentary process and is composed of carbon. Its formation happens on the seafloor. They possess the property of solubility in weak acids and in water. It is present in different colours such as white, yellow or grey.

Complete Step by Step Answer:
Here, we have to find the chemical symbol for limestone. Let's discuss all the options one by one.
Option A is Calcium oxide (CaO). It is a solid of white colour that is obtained due to the roasting of calcium carbonate. In this process, the removal of carbon dioxide from the calcium carbonate occurs. It is also known by the name lime or quicklime. Therefore, it is not the chemical symbol for limestone.

Option B is calcium hydroxide(\[{\rm{Ca(OH}}{{\rm{)}}_{\rm{2}}}\]). It is obtained when calcium oxide undergoes a reaction with water. On dissolving the calcium oxide in water, some amount of CaO dissolves in water and the remaining amount suspends in the solution. This solution is used in whitewash. Therefore, it is also not the chemical symbol for limestone.
The chemical representation of limestone is Calcium carbonate (\[{\rm{CaC}}{{\rm{O}}_{\rm{3}}}\]).
Therefore, option D is right.

Note: Limestone is a versatile mineral that is useful in many ways. Its use in decoration is can be seen in the Taj Mahal of India. In the field of agriculture, it functions as a soil conditioner. It works as a neutralizer of soil's acidity.