Sulfuric acid

Sulfuric acid
Space-filling model
Ball-and-stick model length = 142.2 pm,
S-O bond length = 157.4 pm,
O-H bond length = 97 pm
IUPAC name
Sulfuric acid
Other names
Oil of vitriol
Hydrogen sulfate
3D model (JSmol)
ECHA InfoCard 100.028.763
EC Number
  • 231-639-5
E number E513 (acidity regulators, ...)
RTECS number
  • WS5600000
UN number 1830
  • InChI=1S/H2O4S/c1-5(2,3)4/h(H2,1,2,3,4) Y
  • InChI=1/H2O4S/c1-5(2,3)4/h(H2,1,2,3,4)
  • OS(=O)(=O)O
Molar mass 98.079 g/mol
Appearance Colorless liquid
Odor Odorless
Density 1.8302 g/cm3, liquid[1]
Melting point 10.31[1] °C (50.56 °F; 283.46 K)
Boiling point 337[1] °C (639 °F; 610 K) When sulfuric acid is above 300 °C (572 °F; 573 K), it gradually decomposes to SO3 + H2O
miscible, exothermic
Vapor pressure 0.001 mmHg (20 °C)[2]
Acidity (pKa) -2.8, 1.99
Conjugate base Bisulfate
Viscosity 26.7 cP (20 °C)
a = 818.1(2) pm, b = 469.60(10) pm, c = 856.3(2) pm
α = 90°, β = 111.39(3) pm°, γ = 90°
157 J·mol−1·K−1[4]
−814 kJ·mol−1[4]
GHS labelling:
P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
NFPA 704 (fire diamond)
Flash point Non-flammable
15 mg/m3 (IDLH), 1 mg/m3 (TWA), 2 mg/m3 (STEL)
Lethal dose or concentration (LD, LC):
2140 mg/kg (rat, oral)[5]
50 mg/m3 (guinea pig, 8 hr)
510 mg/m3 (rat, 2 hr)
320 mg/m3 (mouse, 2 hr)
18 mg/m3 (guinea pig)[5]
87 mg/m3 (guinea pig, 2.75 hr)[5]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 1 mg/m3[2]
REL (Recommended)
TWA 1 mg/m3[2]
IDLH (Immediate danger)
15 mg/m3[2]
Safety data sheet (SDS) External MSDS
Related compounds
Related strong acids
Selenic acid
Hydrochloric acid
Nitric acid
Chromic acid
Related compounds
Sulfurous acid
Peroxymonosulfuric acid
Sulfur trioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)

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.[6]

Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; for this reason, it is hygroscopic and readily absorbs water vapor from the air.[6] Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. 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 should not be performed 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 even secondary thermal burns due to dehydration.[7][8] Dilute sulfuric acid is substantially less hazardous without the oxidative and dehydrating properties; however, it should still be handled with care for its acidity.

Sulfuric acid is a very important commodity chemical, and a nation's sulfuric acid production is a good indicator of its industrial strength.[9] It is widely produced with different methods, such as contact process, wet sulfuric acid process, lead chamber process and some other methods.[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 processing, 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, in dehydrating a compound, and in various cleaning agents. Sulfuric acid can be obtained by dissolving sulfur trioxide in water.

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