Sulfuric acid, H2SO4, is a viscous (thick and syrupy), oily liquid which has for years been the most widely used chemical in the world. Over 100 billion lb (45 billion kg) of sulfuric acid are produced each year. It is also one of the least expensive acids, which makes it a favorite of industries around the world. It is used in the production of fertilizers and as an industrial catalyst (a substance which speeds up chemical reactions).
One of the major uses of sulfuric acid is in the production of fertilizers. Phosphate rock is treated with sulfuric acid to produce water soluble phosphates, which are essential for plant growth and survival. It is also the acid used in car batteries. Automobile batteries contain lead, lead oxide, and sulfuric acid. These lead storage batteries are used because they can not only provide the electric current needed to start a car, but can be recharged by the car's electrical system while the car is running.
Sulfuric acid is one of the major components of acid rain. Coal contains sulfur as a natural impurity and when coal is burned sulfur dioxide (SO2) and sulfur trioxide (SO3) gases are produced. Sulfur trioxide then reacts with water in the air, creating sulfuric acid. This acid rain can damage buildings, corrode metal, and destroy plant and animal life. Acid rain is an increasing problem not only in major industrialized nations, but also in neighboring countries that are downwind, since pollutants produced by a country do not stay in the air above that country.
One of the major industrial uses of sulfuric acid is as a dehydrating agent (a substance that removes water from other substances). Sulfuric acid is an extremely effective dehydrating agent. Upon contact with living tissue it kills cells by removing water from them.