The sulfuric acid is the chemistry five big inorganic strong acid (sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid) one. Physical property: The vitriol oil is one kind of achromatic color tasteless oily liquid. In the commonly used strong sulfuric acid the H2SO4 quality score is 98.3%, its density is 1.84g · cm-3, its material's quantity density is 18.4mol · L-1. The sulfuric acid is the strong acid which one kind of high boiling point difficult to volatilize, easy to dissolve in the water, can by compare and Shui Hunrong willfully. When strong sulfuric acid dissolution emits the massive heat, therefore time strong sulfuric acid dilution should “the acid enter the water, along the wall, but actually, stirs unceasingly slowly.” If continues the strong sulfuric acid to pass over the sulfur trioxide, will then have " the smoke introduction " the phenomenon, like this will surpass 98.3% sulfuric acid to be called " the fuming sulfuric acid ".