Sodium hydroxide

ProductType:Chemicals
Product Category:Laboratory chemicals
Call to buy
ArioExir
AboutProduct

Sodium hydroxide
Unit cell, spacefill model of sodium hydroxide
  Sodium, Na
  Oxygen, O
  Hydrogen, H
Sample of sodium hydroxide as pellets in a watchglass
Names
IUPAC name
Sodium hydroxide[3]
Other names
  • Ascarite
  • Caustic soda
  • Lye[1][2]
  • Soda lye
  • Sodium hydrate
  • White caustic[3]
Identifiers
CAS Number
  • 1310-73-2 check
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:32145 check
ChemSpider
  • 14114 check
ECHA InfoCard 100.013.805 Edit this at Wikidata
EC Number
  • 215-185-5
E number E524 (acidity regulators, ...)
Gmelin Reference
68430
KEGG
  • D01169 check
MeSH Sodium+Hydroxide
PubChem CID
  • 14798
RTECS number
  • WB4900000
UNII
  • 55X04QC32I check
UN number 1823 (solid)
1824 (solution)
CompTox Dashboard (EPA)
  • DTXSID0029634 Edit this at Wikidata
 
 
Properties
Chemical formula
NaOH
Molar mass 39.9971 g/mol
Appearance White, opaque crystals
Odor odorless
Density 2.13 g/cm3[4]
Melting point 323 °C (613 °F; 596 K)[4]
Boiling point 1,388 °C (2,530 °F; 1,661 K)[4]
Solubility in water
418 g/L (0 °C)
1000 g/L (25 °C)[4]
3370 g/L (100 °C)
Solubility soluble in glycerol, negligible in ammonia, insoluble in ether, slowly soluble in propylene glycol
Solubility in methanol 238 g/L
Solubility in ethanol <<139 g/L
Vapor pressure <2.4 kPa (20 °C)
0.1 kPa (700 °C)
Acidity (pKa) 15.7
Magnetic susceptibility (χ)
−15.8·10−6 cm3/mol (aq.)[5]
Refractive index (nD)
1.3576
Structure[6]
Crystal structure
Orthorhombic, oS8
Space group
Cmcm, No. 63
Lattice constant
a = 0.34013 nm, b = 1.1378 nm, c = 0.33984 nm
Formula units (Z)
4
Thermochemistry[7]
Heat capacity (C)
59.5 J/(mol·K)
Std molar
entropy (S298)
64.4 J/(mol·K)
Std enthalpy of
formation (ΔfH298)
−425.8 kJ/mol
Gibbs free energy (ΔfG)
-379.7 kJ/mol
Hazards
GHS labelling:
Pictograms
GHS05: Corrosive GHS07: Exclamation mark
Signal word
Danger
Hazard statements
H290H302H314
Precautionary statements
P280P305+P351+P338P310
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond Health 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gas Flammability 0: Will not burn. E.g. water Instability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calcium Special hazard ALK: Alkaline
3
0
1
ALK
Lethal dose or concentration (LD, LC):
LD50 (median dose)
40 mg/kg (mouse, intraperitoneal)[9]
140 - 340 mg/kg (rat, oral)
1350 mg/kg (rabbit, dermal)
LDLo (lowest published)
500 mg/kg (rabbit, oral)[10]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 2 mg/m3[8]
REL (Recommended)
C 2 mg/m3[8]
IDLH (Immediate danger)
10 mg/m3[8]
Safety data sheet (SDS) External SDS
Related compounds
Other anions
  • Sodium hydrosulfide
  • Sodium hydride
  • Sodium oxide
Other cations
  • Lithium hydroxide
  • Potassium hydroxide
  • Rubidium hydroxide
  • Caesium hydroxide
  • Francium hydroxide
Related compounds
  • Sodium deuteroxide
  • Sodium chloroxide

color:
color: