General Description
 Sulfuric acid , also spelled Sulphuric acid, sometimes called Oil Of Vitriol, or Hydrogen Sulfate battery acid, is a dense, colourless, oily, corrosive liquid; more sulfuric acid is produced than any other chemical. It has widely varied uses and plays some part in the production of nearly all manufactured goods.
Pure sulfuric acid with a specific gravity of 1.85. freezes at 10.37° C , boils at 340° C and is soluble in all proportions in water. When heated, the pure acid partially decomposes into water and sulfur trioxide. Sulfuric acid is a very strong acid in aqueous solution; it is largely changed to hydrogen ions (H+) and sulfate ions (SO42-). Each molecule gives two H+ ions, thus sulfuric acid is dibasic, which forms both normal sulfates (with both hydrogens replaced, e.g., sodium sulfate, Na2SO4) and acid sulfates, also called bisulfates or hydrogen sulfates (with only one hydrogen replaced, e.g., sodium bisulfate, NaHSO4).
application
Sulfuric acid is prepared industrially by the reaction of water with sulfur trioxide, which in turn is made by chemical combination of sulfur dioxide and oxygen either by the contact process or the chamber process. The lead chamber process is used to produce much of the acid used to make fertilizers. It produces a relatively dilute acid (62% - 78%). The contact process produces a more concentrated acid but requires purer raw materials and the use of expensive catalysts. Some sulfuric acid is also made from ferrous sulfate waste solutions from pickling iron and steel and from waste acid sludge from oil refineries.
The uses of sulfuric acid are so varied that the volume of its production provides an approximate index of general industrial activity. Its main use is in phosphate fertilizer production, both superphosphate of lime and ammonium sulfate. It is widely also used to manufacture chemicals, e.g., in making hydrochloric acid, nitric acid, sulfate salts, synthetic detergents, dyes and pigments, explosives, drugs, other acids, parchment paper, glue and wood preservatives.
It is used in the purification of petroleum to wash impurities out of gasoline and other refinery products.Sulfuric acid is used in processing metals, e.g., in pickling (cleaning) of metal, electroplating baths, nonferrous metallurgy. Rayon is made with sulfuric acid. In one of its most familiar applications, it serves as the electrolyte in the lead-acid storage battery commonly used in motor vehicles (acid for this use, containing about 33% H2SO4 and with specific gravity about 1.25, is often called battery acid).
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