Sodium hydroxide
| Structural formula | |||
|---|---|---|---|
| |||
| general | |||
| name | sodium hydroxide | ||
| other names | caustic soda, caustic soda, caustic soda solution (aqueous solution) | ||
| sum formula | NaOH | ||
| CAS number | 1310-73-2 | ||
| short description | white, crystalline solid | ||
| characteristics | |||
| mol mass | 40 g mol | ||
| state of aggregation | firmly | ||
| density | 2.13 g/cm ³ | ||
| melting point | 319 °C | ||
| boiling point | 1390 °C | ||
| steam pressure | 0.000 hPa (25°C) | ||
| Solubility | well solubly in water (1260 g/l with 20 °C) | ||
| pH value of the solution | 14 with C = 1 mol/l | ||
| safety reference | |||
| of Gefahrensymbole | |||
| |||
| R and S-sentences |
of R: 35 | ||
| MAK | 2 mg/m 3 | ||
| as far as possible and common, become SI-UNITs uses. If not differently notes, the indicated data apply with standard conditions. | |||
Sodium hydroxide (also caustic soda, caustic soda), chemical formula NaOH, is a white hygroscopic solid with a melting point of 319 °C and a density of 2,13g/cm 3. In water it dissolves under large heat development to the strongly alkalinely reacting caustic soda solution . With the carbon dioxide it reacts to air to Natriumcarbonat and must be kept therefore in locked containers. As a strong cousin it displaces weakerand volatile Basen from their salts.
Table of contents |
production
- conversion of Natriumcarbonat with calcium hydroxide to sodium hydroxide and calcium carbonate:
<math> \ mathrm {Na_2CO_3 + approx. (OH) _2 \ rightarrow 2 \, NaOH + CaCO_3}< /math>
The little solubleCalcium carbonate is filtered off. In the filtrate the well soluble sodium hydroxide remains.
- Electrolysis from sodium chloride to caustic soda solution, hydrogen and Chlorgas (chlorine alkali electrolysis).
Several industrielle procedures exist:
- Amalgam procedures
- diaphragm procedure
- diaphragm procedure
(see also Chlor-Alkali-Elektrolyse)
all procedures commonly are additional cleaning and concentration stages,in order to arrive at water-free sodium hydroxide.
- In the laboratory one can win sodium hydroxide by reaction of elementary sodium with water under formation of caustic soda solution and hydrogen (1). After the evaporation of the caustic soda solution firm sodium hydroxide remains back (2).
use
- production of soaps
- production of coloring materials
- production of cellulose from wood and straw
- production of celanese
- Merzerisieren of cotton
- fat, oil and petroleum cleaning
- bauxite explanation (preliminary stage in the aluminum production)
- Synthesis of different chemicals (for example sodium hypochlorite, sodium phosphate, Natriumsulfid, sodium aluminate)
- production of entmineralisiertem water: Regeneration by Ionentauschern
- developing exposed plate material in electronics
- a component of tubing cleaners
- production of Brezeln for the brown colouring and the “seifigen”,Taste
- recovery of full demineralizers for laboratory and aquarium need
- corroding brass german silver and copper plates for the model construction amateur
- Säurebestimmung of wine by means of blue caustic solution
of safety references
- ways going blind danger is to be used an eye protector.
- Schutzhandschuhe wear.
- In a closely locked plastic containerkeep.
