what is economic importance of calcium carbonate

Why is calcium carbonate used in agriculture

Q. What is calcium carbonate is used for.

Q. What is the percentage of calcium in calcium carbonate $\left(CaC{O}_3\right)$?

Q. What is the oxidation state of calcium in calcium carbonate ($Ca{CO}_3$)?

Q.

4.5 moles of calcium carbonate are reacted with dilute hydrochloric acid.
(i) Write the equation for the reaction.
(ii) What is the mass of 4.5 moles of calcium carbonate? (Relative molecular mass of calcium carbonate is 100).
(iii) What is the volume of carbon dioxide liberated at stp?
(iv) What mass of calcium chloride is formed? (Relative molecular mass of calcium chloride is 111)
(v) How many moles of HCl are used in this reaction?

Q. What is the percentage by weight of calcium in calcium carbonate ($CaC{O}_3$)?