The correct option is 1 only
Explanation
Limestone is a non-metallic mineral composed principally of calcium carbonate ($CaCO_3$). It is a critical raw material for construction and heavy industries, particularly for the production of cement and the smelting of iron ore.
Statement 1 is Correct:
Limestone is a sedimentary rock. It is formed primarily in shallow marine environments through the accumulation of shell, coral, algal, and fecal debris (organic sedimentary rocks) or through chemical precipitation (chemical sedimentary rocks). It is typically found in sedimentary basins.
Statement 2 is Incorrect:
While limestone is the primary raw material for the cement industry, the claim that it has no application in iron smelting is factually wrong. In the iron and steel industry, limestone is used as a flux in the blast furnace. It lowers the melting point of the ore and combines with impurities, such as silica, to form molten slag (calcium silicate), which is then separated from the molten iron.
Key Takeaway:
Limestone is a sedimentary rock that serves as the backbone of the cement industry and acts as an essential flux in the iron and steel industry to remove impurities.