Sulfuric acid
Sulfuric acid (sulphuric acid).
Molecular formula: H2SO4
(O = 65,25 %, S = 32,69 %, H = 2,06 %)

Molar mass = 98,078 ± 0,006 g·mol-1

Formerly called oil of vitriol. It is a mineral acid whose strength (pKa = -3.0) is only exceeded by a few super-acids. It is miscible with water in all proportions where it dissociates releasing hydronium cations H3O+:

2 H2O + H2SO4 >>> 2 H3O+ + SO42-

Pure sulfuric acid is a viscous, colorless and odorless liquid. Various impurities often brown yellow color. Sometimes its concentration is expressed in degrees Baumé (symbol ° Be '), which actually measure the density of liquid, which varies significantly depending on the content of sulfuric acid.
Because hygroscopic nature of its, it can be used for drying. It is therefore industrially used as drying agent (when it absorbs water or water vapor of the substance to be dried, it is diluted).
Pure sulfuric acid is not encountered naturally on Earth in anhydrous form, due to its great affinity for water, it is nevertheless found in some volcanic lakes (see link on Hydro-Land) and acid rain, which results from the oxidation of acid H2SO3 sulfur resulting from the dissolution of sulfur dioxide SO2 in the clouds, sulfur dioxide is itself produced by the sulfur-containing fossil fuels.

Today the major industrial process most widely used, is called "contact process" because requires contact with a catalyst. It will be generated by hydration of sulfur trioxide SO3, itself resulting from the natural oxidation of sulfur dioxide SO2.
It can be produced with a purity of 100% substantially, but it tends to release sulfur trioxide, approaching its boiling points of 337° C (610 K), where it gives the acid as 98, 3%, corresponding to the azeotrope with equilibrium water:

H2SO4 <<>> SO3 + H2O (DH = 177 kJ·mol-1)

Main Features:

Mass fraction % H2SO4
>95 %
Density  (liquid)
1830 kg/m3
Boiling point (decomposition)
337 °C (639 °F; 610 K)

Technical solutions:

In water treatment, it is used by injection in water with a diluted reagent (solutions).
The dissolution process is exothermic, and above 50° C can be rapidly reached.

A formulation for water treatment.
Reaction mechanism of calcium bicarbonates (simplified equations):

H2SO4 + Ca[HCO3]2 >>> 2 CO2 + H2O + CaSO4
.98.........162 or 10°F..... (2x44=88) ............136

With 1 mg as H2SO4 added, there has (10/98) = 0.102° F for lower TAC, and 0.898 mg as free CO2 and (96/98) = 0,98 mg/L as SO4 formed.

Tightly closed and dry in a well ventilated area.
Storage temperature: no restrictions.



Sources : personal and Wikipedia, the free encyclopedia.

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