Product Description
Sodium hydroxide, commonly referred to as caustic soda, bears the chemical formula NaOH. As a highly corrosive strong-base compound, it generally exists in the form of white flakes or granules. It dissolves easily in water to form an alkaline solution and is also soluble in methanol and ethanol. Due to its deliquescent nature, it absorbs airborne moisture as well as acidic gases such as carbon dioxide.
Widely applied across numerous industrial fields, sodium hydroxide is vital for manufacturing paper pulp, textiles, soap and various detergents. It is also a key ingredient in household alkaline drain-cleaning products.
Chemical Properties
| Melting point | 681 °C(lit.) |
| Boiling point | 1390°C |
| density | 1.515 g/mL at 20 °C |
| vapor density | <1 (vs air) |
| vapor pressure | 1 mm Hg ( 745 °C) |
| refractive index | 1,473-1,475 |
| Fp | 176-178°C |
| storage temp. | room temp |
| solubility | H2O: 1 M at 20 °C, clear, colorless |
| form | beads |
| color | White |
| Specific Gravity | 2.13 |
| Odor | Odorless |
| PH Range | 13 - 14 |
| PH | 10.98(1 mM solution);11.95(10 mM solution);12.88(100 mM solution); |
| Water Solubility | SOLUBLE |
| Sensitive | Air Sensitive & Hygroscopic |
| Decomposition | 176-178 ºC |
| λmax | λ: 260 nm Amax: 0.015 |
| λ: 280 nm Amax: 0.01 | |
| Merck | 148,627 |
| Dielectric constant | 57.5（25℃） |
| Exposure limits | TLV-TWA air 2 mg/m3 (OSHA); ceiling 2 mg/m3 (ACGIH) and 2 mg/m3/15 min (NIOSH). |
| Stability: | hygroscopic |
| CAS DataBase Reference | 1310-73-2(CAS DataBase Reference) |
| NIST Chemistry Reference | Sodium hydroxide(1310-73-2) |
| EPA Substance Registry System | Sodium hydroxide (1310-73-2) |
Safety Information
| Hazard Codes | C,Xi |
| Risk Statements | 36/38-35-34 |
| Safety Statements | 26-45-37/39-24/25-36/37/39 |
| RIDADR | UN 1824 8/PG 2 |
| WGK Germany | 1 |
| RTECS | TT2975000 |
| F | 8 |
| TSCA | Yes |
| HS Code | 2815 11 00 |
| HazardClass | 8 |
| PackingGroup | II |
| Hazardous Substances Data | 1310-73-2(Hazardous Substances Data) |
| Toxicity | LD orally in rabbits: 500 mg/kg (10% soln) (Fazekas) |
| IDLA | 10 mg/m3 |
Product Application
Sodium hydroxide boasts extensive application prospects. In chemical laboratory settings, it functions both as a common reagent and an alkaline desiccant, thanks to its strong hygroscopicity. Caustic soda holds a crucial position in national economic development and is indispensable to multiple industrial sectors. The chemical manufacturing industry is its biggest consumer, followed by papermaking, aluminum and tungsten smelting, viscose fiber production, and soap-making. It is also utilized in the synthesis of dyes, plastics, pharmaceuticals and organic intermediates, reclaimed rubber processing, metallic sodium electrolysis, water treatment, and the production of inorganic salts including borax, chromium salts, manganates and phosphates.
Industrial-grade sodium hydroxide is required to comply with national standard GB209-2006;ion-exchange-membrane-grade industrial sodium hydroxide follows GB/T11199-89;chemical-fiber-grade sodium hydroxide meets GB11212-89;and food-grade sodium hydroxide conforms to GB5175-85.
Industrially, sodium hydroxide is widely known as caustic soda, a term originating from the severe skin burns caused by its concentrated solutions. It dissolves proteins, resulting in alkali burns that take longer to heal than acid burns. Instilling a 0.02% sodium hydroxide solution into rabbit eyes may injure the corneal epithelium. Relevant toxicity data show an intraperitoneal LD50 of 40 mg/kg in mice and an oral LDLo of 500 mg/kg in rabbits. Its dust irritates the eyes and respiratory tract, erodes the nasal septum, and damages skin and particularly mucous membranes, forming soft scabs that may penetrate deep tissue and leave permanent scars.
