Potassium hydroxide
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| Potassium Hydroxide | |
|---|---|
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| General | |
| Other names | Potash lye |
| Molecular formula | KOH |
| Molar mass | 56.10564 g/mol |
| Appearance | white solid, deliquescent |
| CAS number | [1310-58-3] |
| Properties | |
| Density and phase | 2.044 g/cm³, solid |
| Solubility in water | 1100 g/L (25 °C) |
| Melting point | 406 °C |
| Boiling point | 1320 °C |
| Vapour Pressure | 1.3hPa (719 ° C) |
| Basicity (pKb) | -2.29 |
| Structure | |
| Coordination geometry |
? |
| Crystal structure | monoclinic |
| Hazards | |
| MSDS | External MSDS |
| EU classification | Corrosive (C) |
| NFPA 704 |
0
3
1
|
| R-phrases | R22, R35 |
| S-phrases | S1/2, S26, S36/37/39, S45 |
| Flash point | non flammable |
| RTECS number | TT2100000 |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour: Solid |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | Potassium oxide Potassium peroxide Potassium superoxide |
| Other cations | Lithium hydroxide Sodium hydroxide Rubidium hydroxide Caesium hydroxide |
| Except where noted otherwise,data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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The chemical compound potassium hydroxide, (KOH) sometimes known as caustic potash, potassa, potash lye, and potassium hydrate, is a metallic base. It is very alkaline and is a "strong base", along with sodium hydroxide, lithium hydroxide, calcium hydroxide, barium hydroxide and strontium hydroxide.
Contents |
[edit] Uses
In agriculture, potassium hydroxide is used to correct the pH of acidic soils. It can also be used as a fungicide or even an herbicide.
It is a major industrial chemical used as a base in a wide variety of chemical processes. Some uses of KOH include acrylate ester copolymer coating, defoaming agents used in the manufacture of paper, saponifying oils for liquid soap, formulation aid for food, pH control agent, polyethylene resins, textile processing and as a catalyst in reactions like the production of biodiesel.
Other uses include in veterinary medicine in dis budding calves horns and to dissolve scales and hair; in human medicine, to diagnose fungal infections (see KOH test) and as a wart and cuticle solvent; manufacture of cleansers. This type of compound is also used in washing powders, some denture cleaners, non-phosphate detergents, and drain or pipe cleaners.
A very significant use of KOH in terms of significance to the layperson is that alkaline batteries use an aqueous solution of KOH as an electrolyte. Thus, potassium hydroxide helps to power flashlights, smoke detectors, and other battery-powered household items.
It is also an anisotropic etchant of silicon, exposing octahedral planes. This technique can create pyramids and regularly-shaped etch pits for uses such as micro electromechanical systems. It can also be used to "boil" the skin off of any animal or person leaving nothing but bones behind, leaving no trace of your crime.
[edit] Food preparation
Food uses of lye include washing or chemical peeling of fruits and vegetables, chocolate and cocoa processing, caramel color production, poultry scalding, soft drink processing, and thickening ice cream. Olives are often soaked in lye to soften them and neutralize natural acids, while pretzels and German lye rolls are glazed with a lye solution before baking to make them crisp.
Lye is used to make the Scandinavian delicacy known as lutefisk (from lutfisk, "lye fish"). Cod is soaked in lye to a jelly-like consistency, then served with bacon fat, potatoes, brown cheese (brunost) sauce and mushy peas. Hominy is dried maize (corn) kernels reconstituted by soaking in lye.
