Metallurgy

Smelting is a process in which ore is heated with a reducing agent (like carbon) to extract metal.
In the case of iron ore, the correct reaction that represents smelting is: This is a reduction reaction where iron(III) oxide reacts with carbon to form iron and carbon monoxide.

Limestone is commonly used in metallurgical processes to remove acidic impurities.
It acts as a flux by reacting with impurities like silica to form a slag.
This slag can then be removed, leaving behind the pure metal.