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Sulfuric acid

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**Physical Properties:**
– Boiling point of 337°C
– Solubility in water is miscible and exothermic
– Acidity with pKa of -2.8
– Viscosity of 26.7 cP (20°C)
– Crystal structure is monoclinic

**Grades of Sulfuric Acid:**
– Diluted sulfuric acid: 29% concentration, density 1.00-1.25 kg/L
– Battery acid: 29-32% concentration, density 1.25-1.28 kg/L
– Chamber acid/fertilizer acid: 62-70% concentration, density 1.52-1.60 kg/L
– 66 °Bé (66-degree Baumé) acid: 93.2% concentration, density 1.83 kg/L
– Concentrated sulfuric acid: 98.3% concentration, density 1.84 kg/L

**Chemical Properties:**
– Strong acid with acid dissociation constant
– Formation of bisulfate anion
Dehydration properties
Dehydration of table sugar
– Formation of carbon snake from sucrose

– Sulfuric acid reacts with most bases to give the corresponding sulfate or bisulfate.
– Treating potassium nitrate with sulfuric acid produces nitric acid.
– Sulfuric acid reacts as an acid and a dehydrating agent when combined with nitric acid.
– Dilute sulfuric acid reacts with many metals, producing hydrogen gas and salts.
– Concentrated sulfuric acid can serve as an oxidizing agent, releasing sulfur dioxide.

**Occurrence and Uses:**
– Dilute sulfuric acid is a constituent of acid rain formed by atmospheric oxidation of sulfur dioxide.
– Sulfuric acid is used in the production of detergents, synthetic resins, dyestuffs, pharmaceuticals, and more.
– Around 60% of sulfuric acid is used for fertilizers, 20% in the chemical industry, 6% in pigments, with the rest in various applications.
– Used in oil well acidicizing, aluminum reduction, paper sizing, water treatment, production of explosives, textiles, lubricants, non-ferrous metals, and batteries.

**Safety and Industrial Applications:**
– Sulfuric acid causes severe burns, decomposing proteins and lipids.
– Used in the production of phosphoric acid, dyestuffs, iron and steelmaking, and as an electrolyte in lead-acid batteries.
– Used as a cleaning agent in the iron and steelmaking industry, with spent acid recycled using regeneration plants.
– Acts as a catalyst in chemical reactions, in the production of nylon, and in petroleum refining for increasing octane rating of gasoline.
– Legal restrictions control the commerce of sulfuric acid due to its potential use in illicit drug manufacturing.

Sulfuric acid (Wikipedia)

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.

Sulfuric acid
Space-filling model
Ball-and-stick model
S=O bond 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 Edit this at Wikidata
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) checkY
  • InChI=1/H2O4S/c1-5(2,3)4/h(H2,1,2,3,4)
  • OS(=O)(=O)O
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
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)
a = 818.1(2) pm, b = 469.60(10) pm, c = 856.3(2) pm
α = 90°, β = 111.39(3)
°, γ = 90°
157 J/(mol·K)
−814 kJ/mol
GHS labelling:
GHS05: Corrosive GHS06: Toxic
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)
  • 50 mg/m3 (guinea pig, 8 hr)
  • 510 mg/m3 (rat, 2 hr)
  • 320 mg/m3 (mouse, 2 hr)
  • 18 mg/m3 (guinea pig)
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
Safety data sheet (SDS) External MSDS
Related compounds
Related strong acids
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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. 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. 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; a country's sulfuric acid production is a good indicator of its industrial strength. Many methods for its production are known, including the contact process, the wet sulfuric acid process, and the lead chamber process. Sulfuric acid is also a key substance in the chemical industry. It is most commonly used in fertilizer manufacture 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, 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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