Sulfuric Acid

Title: Sulfuric Acid
CAS Registry Number: 7664-93-9
Additional Names: Oil of vitriol
Molecular Formula: H2O4S
Molecular Weight: 98.08
Percent Composition: H 2.06%, O 65.25%, S 32.69%
Line Formula: H2SO4
Literature References: Prepd by the Contact Process according to the reactions 2SO2 + O2 ® 2SO3, and SO3 + H2O ® H2SO4; by the Chamber Process according to the reactions 2NO + O2 ® 2NO2, and NO2 + SO2 + H2O ® H2SO4 + NO. Sulfuric acid of commerce contains 93-98% H2SO4; the remainder is water. Monograph: W. W. Duecker, J. R. West, The Manufacture of Sulfuric Acid (Reinhold, New York, 1959) 515 pp. Review of manuf: Pearce, "Sulphuric Acid: Physico-Chemical Aspects of Manufacture" in Inorganic Sulphur Chemistry, G. Nickless, Ed. (Elsevier, New York, 1968) pp 535-561; Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 795-806. Toxicity data: H. F. Smyth et al., Am. Ind. Hyg. Assoc. J. 30, 470 (1969). Review of toxicology and human exposure: Toxicological Profile for Sulfur Trioxide and Sulfuric Acid (PB99-122038, 1998) 224 pp.
Properties: Clear, colorless, odorless, oily liquid. Very corrosive! Has a very great affinity for water, abstracting it from the air and also from many organic substances; hence it chars sugar, wood, etc. d ~1.84. bp ~290°; dec 340° into sulfur trioxide and water. mp 10° (anhydrous acid). 98% H2SO4 freezes at +3°; 93% at -32°; 78% at -38°; 74% at -44°; 65% at -64°. Misc with water and alcohol with the generation of much heat and with contraction in vol. When diluting, the acid should be added to the diluent. Keep tightly closed. Handle with caution. Avoid contact with skin. LD50 orally in rats: 2.14 g/kg (Smyth).
Melting point: mp 10° (anhydrous acid)
Boiling point: bp ~290°
Density: d ~1.84
Toxicity data: LD50 orally in rats: 2.14 g/kg (Smyth)
Derivative Type: Sulfuric acid, fuming
CAS Registry Number: 8014-95-7
Properties: H2SO4 with free SO3, designated in commerce as oleum. Available grades contain up to about 80% free SO3. Colorless or slightly colored, viscous liquid, emitting choking fumes of sulfur trioxide. Extremely corrosive. Handle with great care. Avoid contact with skin. Keep tightly closed in glass-stoppered bottles.
CAUTION: Potential symptoms of overexposure are eye, skin, nose and throat irritation; pulmonary edema, bronchitis; emphysema; conjunctivitis; stomatis; dental erosion; tracheobronchitis; skin and eye burns; dermatitis. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 290. See also Clinical Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins, Baltimore, 5th ed., 1984) section III, pp 8-12. Occupational exposure to strong inorganic acid mists containing sulfuric acid is listed as a known human carcinogen: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-234.
Use: In manuf of fertilizers, explosives, dyestuffs, other acids, parchment paper, glue, purification of petroleum, pickling of metal.
Therap-Cat: Dil acid formerly in treatment of gastric hypoacidity. Concd acid formerly as a topical caustic.
Sulfurous Acid Sulfuryl Chloride Sulfuryl Fluoride Sulindac Sulisatin

Sulfuric acid
S=O bond length = 142.2 pm, S-O bond length = 157.4 pm, O-H bond length = 97 pm
Space-filling model
Ball-and-stick model
Sulphuric acid 96 percent extra pure.jpg
CAS number 7664-93-9 YesY
ChemSpider 1086 YesY
EC number 231-639-5
UN number 1830
KEGG D05963 YesY
ChEBI CHEBI:26836 YesY
RTECS number WS5600000
Jmol-3D images Image 1
Molecular formula H
Molar mass 98.079 g/mol
Appearance Clear, colorless, odorless liquid
Density 1.84 g/cm3, liquid
Melting point 10 °C; 50 °F; 283 K
Boiling point 337 °C; 639 °F; 610 K (When sulfuric acid is above 300 °C, it will decompose slowly)
Solubility in water miscible
Acidity (pKa) −3, 1.99
Viscosity 26.7 cP (20 °C)
Std molar
entropy So298
157 J·mol−1·K−1[1]
Std enthalpy of
formation ΔfHo298
−814 kJ·mol−1[1]
MSDS External MSDS
GHS pictograms The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word Danger
GHS hazard statements H314
GHS precautionary statements P260, P264, P280, P301+330+331, P303+361+353, P363, P304+340, P305+351+338, P310, P321, P310, P405, P501
EU Index 016-020-00-8
EU classification Corrosive CDangerous for the Environment (Nature) N[2][3]
R-phrases R35
S-phrases (S1/2) S26 S30 S45
NFPA 704
NFPA 704.svg
Flash point Non-flammable
Threshold Limit Value 15 mg/m3 (IDLH), 1 mg/m3 (TWA), 2 mg/m3 (STEL)
LD50 2140 mg/kg (oral, rat), LC50 = 25 mg/m3 (inhalation, rat)
Related compounds
Related strong acids Selenic acid
Hydrochloric acid
Nitric acid
Chromic acid
Related compounds Sulfurous acid
Peroxymonosulfuric acid
Sulfur trioxide
Supplementary data page
Structure and
n, εr, etc.
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Sulfuric acid (alternative spelling sulphuric acid) is a highly corrosive strong mineral acid with the molecular formula H2SO4. It is a pungent-ethereal, colorless to slightly yellow viscous liquid which is soluble in water at all concentrations.[4] Sometimes, it is dyed dark brown during production to alert people to its hazards.[5] The historical name of this acid is oil of vitriol.[6]

Sulfuric acid is a diprotic acid and shows different properties depending upon its concentration. Its corrosiveness on other materials, like metals, living tissues (e.g. skin and flesh) or even stones, can be mainly ascribed to its strong acidic nature and, if concentrated, strong dehydrating and oxidizing property. Sulfuric acid at a high concentration can cause very serious damage upon contact, as it not only causes chemical burns via hydrolysis, but also secondary thermal burns via dehydration. It burns the cornea and can lead to permanent blindness if splashed onto eyes. Accordingly, safety precautions should be strictly observed when handling it. Moreover, it is hygroscopic, readily absorbing water vapour from the air.[4]

Sulfuric acid has a wide range of applications including domestic acidic drain cleaner,[7] electrolyte in lead-acid batteries and various cleaning agents. It is also a central substance in the chemical industry. Principal uses include mineral processing, fertilizer manufacturing, oil refining, wastewater processing, and chemical synthesis. It is widely produced with different methods, such as contact process, wet sulfuric acid process and some other methods.