Nitric acid

Nitric acid

Pure nitric acid
Resonance description of the bonding in the nitric acid molecule
Ball-and-stick model of nitric acid
Ball-and-stick model of nitric acid
Resonance space-filling model of nitric acid
Resonance space-filling model of nitric acid
Names
IUPAC name
Nitric acid
Other names
  • Aqua fortis
  • Spirit of niter
  • Eau forte
  • Hydrogen nitrate
  • Acidum nitricum
Identifiers
3D model (JSmol)
3DMet
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.028.832 Edit this at Wikidata
EC Number
  • 231-714-2
1576
KEGG
MeSH Nitric+acid
RTECS number
  • QU5775000
UNII
UN number 2031
  • InChI=1S/HNO3/c2-1(3)4/h(H,2,3,4) checkY
    Key: GRYLNZFGIOXLOG-UHFFFAOYSA-N checkY
  • InChI=1/HNO3/c2-1(3)4/h(H,2,3,4)
    Key: GRYLNZFGIOXLOG-UHFFFAOYAO
  • [N+](=O)(O)[O-]
  • ON(=O)=O
Properties
HNO3
Molar mass 63.012 g·mol−1
Appearance Colorless liquid[1]
Odor Acrid, suffocating[1]
Density 1.51 g/cm3, 1.41 g/cm3 [68% w/w]
Melting point −42 °C (−44 °F; 231 K)
Boiling point 83 °C (181 °F; 356 K) 68% solution boils at 121 °C (250 °F; 394 K)
Miscible
log P −0.13[2]
Vapor pressure 48 mmHg (20 °C)[1]
Acidity (pKa) −1.4[3]
Conjugate base Nitrate
−1.99×10−5 cm3/mol
1.397 (16.5 °C)
2.17 ± 0.02 D
Thermochemistry
146 J/(mol·K)[4]
−207 kJ/mol[4]
Hazards
GHS labelling:
GHS03: OxidizingGHS05: CorrosiveGHS06: Toxic
Danger
H272, H290, H314, H331
P210, P220, P280, P303+P361+P353, P304+P340+P310, P305+P351+P338
NFPA 704 (fire diamond)
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
138 ppm (rat, 30 min)[1]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 2 ppm (5 mg/m3)[1]
REL (Recommended)
TWA 2 ppm (5 mg/m3)
ST 4 ppm (10 mg/m3)[1]
IDLH (Immediate danger)
25 ppm[1]
Safety data sheet (SDS) ICSC 0183
Related compounds
Other anions
Nitrous acid
Other cations
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Nitric acid is an inorganic compound with the formula HNO3. It is a highly corrosive mineral acid.[6] The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water. When the solution contains more than 86% HNO3, it is referred to as fuming nitric acid. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as red fuming nitric acid at concentrations above 86%, or white fuming nitric acid at concentrations above 95%.

Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as synthetic dyes and medicines (e.g metronidazole). Nitric acid is also commonly used as a strong oxidizing agent.

  1. ^ a b c d e f g NIOSH Pocket Guide to Chemical Hazards. "#0447". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ "nitric acid_msds".
  3. ^ Bell, R. P. (1973), The Proton in Chemistry (2nd ed.), Ithaca, NY: Cornell University Press
  4. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN 978-0-618-94690-7.
  5. ^ "Safety Data Sheet" (PDF). fishersci.com. Fisher Scientific International. 23 March 2015. p. 2. Archived (PDF) from the original on 10 September 2022. Retrieved 4 October 2022.
  6. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 465–471. ISBN 978-0-08-037941-8.