• # question_answer 1) Describe the importance of: (i) limestone (ii) Cement(iii) Plaster of Paris.

(i) Limestone: It is used as a building material and in the manufacture of cement and quick lime. Specially precipitated $CaC{{O}_{3}}$ is extensively used in the manufacture of high quality paper. It is used as antacid, mild abrasive in toothpaste, as constituent of chewing gum and as a filler in cosmetics. (ii) Cement: It is an important building material. It is used in concrete and reinforced concrete, in plastering and in the construction of every type of structures such as bridges, dams and buildings. (iii) Plaster of Paris: The largest use of plaster of Paris is in the building industry as well as in plasters. It is used for immobilising the affected part of an organ when there is a bone fracture or sprain. It is also employed in dentistry, in ornamental work and for making casts of statues and busts.