Sulfuric acid

Sulfuric acid
S=O	142.2 pm
S−O	157.4 pm
O−H	97 pm
Names
	IUPAC name Sulfuric acid
	Other names Oil of vitriol; Hydrogen sulfate; Dihydrogen sulfate;
Identifiers
CAS Number	7664-93-9 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:26836 ;
ChEMBL	ChEMBL572964 ;
ChemSpider	1086 ;
ECHA InfoCard	100.028.763
EC Number	231-639-5;
E number	E513 (acidity regulators, ...)
Gmelin Reference	2122
KEGG	D05963 ;
PubChem CID	1118;
RTECS number	WS5600000;
UNII	O40UQP6WCF ;
UN number	1830
CompTox Dashboard (EPA)	DTXSID5029683 ;
	InChI InChI=1S/H2O4S/c1-5(2,3)4/h(H2,1,2,3,4) Key: QAOWNCQODCNURD-UHFFFAOYSA-N ; InChI=1/H2O4S/c1-5(2,3)4/h(H2,1,2,3,4) Key: QAOWNCQODCNURD-UHFFFAOYAC;
	SMILES OS(=O)(=O)O;
Properties
Chemical formula	H2SO4, sometimes expressed (HO)2SO2
Molar mass	98.079 g/mol
Appearance	Colorless viscous liquid
Odor	Odorless
Density	1.8302 g/cm3, liquid
Melting point	10.31 °C (50.56 °F; 283.46 K)
Boiling point	337 °C (639 °F; 610 K) ; When sulfuric acid is above 300 °C (572 °F; 573 K), it gradually decomposes to SO3 + H2O
Solubility in water	miscible, exothermic
Vapor pressure	0.001 mmHg (20 °C)
Acidity (pKa)	pKa1 = −2.8; pKa2 = 1.99
Conjugate base	Bisulfate
Viscosity	26.7 cP (20 °C)
Structure
Crystal structure	monoclinic
Space group	C2/c
Lattice constant	a = 818.1(2) pm, b = 469.60(10) pm, c = 856.3(2) pm α = 90°, β = 111.39(3)°, γ = 90°
Formula units (Z)	4
Thermochemistry
Std molar; entropy (S⦵298)	157 J/(mol·K)
Std enthalpy of; formation (ΔfH⦵298)	−814 kJ/mol
Enthalpy of vaporization (ΔfHvap)	56 kJ/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314
Precautionary statements	P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
NFPA 704 (fire diamond)	3 0 2 W; OX
Flash point	Non-flammable
Threshold limit value (TLV)	15 mg/m3 (IDLH), 1 mg/m3 (TWA), 2 mg/m3 (STEL)
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	2140 mg/kg (rat, oral)
LC50 (median concentration)	50 mg/m3 (guinea pig, 8 hr); 510 mg/m3 (rat, 2 hr); 320 mg/m3 (mouse, 2 hr); 18 mg/m3 (guinea pig);
LCLo (lowest published)	87 mg/m3 (guinea pig, 2.75 hr)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 1 mg/m3
REL (Recommended)	TWA 1 mg/m3
IDLH (Immediate danger)	15 mg/m3
Related compounds
Related strong acids	Selenic acid; Hydrochloric acid; Nitric acid; Perchloric acid; Fluoroantimonic acid; Chromic acid;
Related compounds	Sulfurous acid; Peroxymonosulfuric acid; Sulfur trioxide; Oleum;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula H₂SO₄. It is a colorless, odorless, and viscous liquid that is miscible with water.^[7]

Pure sulfuric acid does not occur naturally due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air.^[7] Concentrated sulfuric acid is a strong oxidant with powerful dehydrating properties, making it highly corrosive towards other materials, from rocks to metals. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid but, to the contrary, dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus, the reverse procedure of adding water to the acid is generally avoided since the heat released may boil the solution, spraying droplets of hot acid during the process. Upon contact with body tissue, sulfuric acid can cause severe acidic chemical burns and secondary thermal burns due to dehydration.^[8]^[9] Dilute sulfuric acid is substantially less hazardous without the oxidative and dehydrating properties; though, it is handled with care for its acidity.

Many methods for its production are known, including the contact process, the wet sulfuric acid process, and the lead chamber process.^[10] Sulfuric acid is also a key substance in the chemical industry. It is most commonly used in fertilizer manufacture^[11] but is also important in mineral processing, oil refining, wastewater treating, and chemical synthesis. It has a wide range of end applications, including in domestic acidic drain cleaners,^[12] as an electrolyte in lead-acid batteries, as a dehydrating compound, and in various cleaning agents. Sulfuric acid can be obtained by dissolving sulfur trioxide in water.

^ ^a ^b ^c Haynes, William M. (2014). CRC Handbook of Chemistry and Physics (95 ed.). CRC Press. pp. 4–85. ISBN 9781482208689. Retrieved 18 November 2018.
^ ^a ^b ^c ^d NIOSH Pocket Guide to Chemical Hazards. "#0577". National Institute for Occupational Safety and Health (NIOSH).
^ Kemnitz, E.; Werner, C.; Trojanov, S. (15 November 1996). "Reinvestigation of Crystalline Sulfuric Acid and Oxonium Hydrogensulfate". Acta Crystallographica Section C Crystal Structure Communications. 52 (11): 2665–2668. Bibcode:1996AcCrC..52.2665K. doi:10.1107/S0108270196006749.
^ ^a ^b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 978-0-618-94690-7.
^ "PubChem Compound Summary for CID 1118, Sulfuric Acid". PubChem. National Center for Biotechnology Information. Retrieved 14 January 2025. 3.2.17 Heat of Vaporization.
^ ^a ^b ^c "Sulfuric acid". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b "Sulfuric acid safety data sheet" (PDF). arkema-inc.com. Archived from the original (PDF) on 17 June 2012. Clear to turbid oily odorless liquid, colorless to slightly yellow.
^ Cite error: The named reference OA was invoked but never defined (see the help page).
^ "BASF Chemical Emergency Medical Guidelines – Sulfuric acid (H2SO4)" (PDF). BASF Chemical Company. 2012. Archived from the original (PDF) on 14 June 2019. Retrieved 18 December 2014.
^ Hermann Müller "Sulfuric Acid and Sulfur Trioxide" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. 2000 doi:10.1002/14356007.a25_635
^ "Sulfuric acid". essentialchemicalindustry.org.
^ Cite error: The named reference dc was invoked but never defined (see the help page).

[CRCHCP-1] Haynes, William M. (2014). CRC Handbook of Chemistry and Physics (95 ed.). CRC Press. pp. 4–85. ISBN 9781482208689. Retrieved 18 November 2018.

[PGCH-2] NIOSH Pocket Guide to Chemical Hazards. "#0577". National Institute for Occupational Safety and Health (NIOSH).

[kemnitz-3] Kemnitz, E.; Werner, C.; Trojanov, S. (15 November 1996). "Reinvestigation of Crystalline Sulfuric Acid and Oxonium Hydrogensulfate". Acta Crystallographica Section C Crystal Structure Communications. 52 (11): 2665–2668. Bibcode:1996AcCrC..52.2665K. doi:10.1107/S0108270196006749.

[b1-4] Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 978-0-618-94690-7.

[pubchem-5] "PubChem Compound Summary for CID 1118, Sulfuric Acid". PubChem. National Center for Biotechnology Information. Retrieved 14 January 2025. 3.2.17 Heat of Vaporization.

[IDLH-6] "Sulfuric acid". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[ds-7] "Sulfuric acid safety data sheet" (PDF). arkema-inc.com. Archived from the original (PDF) on 17 June 2012. Clear to turbid oily odorless liquid, colorless to slightly yellow.

[OA-8] Cite error: The named reference OA was invoked but never defined (see the help page).

[TB-9] "BASF Chemical Emergency Medical Guidelines – Sulfuric acid (H2SO4)" (PDF). BASF Chemical Company. 2012. Archived from the original (PDF) on 14 June 2019. Retrieved 18 December 2014.

[10] Hermann Müller "Sulfuric Acid and Sulfur Trioxide" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. 2000 doi:10.1002/14356007.a25_635

[11] "Sulfuric acid". essentialchemicalindustry.org.

[dc-12] Cite error: The named reference dc was invoked but never defined (see the help page).

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