| Potassium Hydroxide |
|---|
 Potassium hydroxide |
| 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 | 360 °C |
| Boiling point | 1320 °C |
| Vapour Pressure | 1.3hPa (719 ° C) |
| Basicity (p''K''b) | -2.29 |
| Structure |
|---|
Coordination geometry | ? |
| Crystal structure | monoclinic |
| Hazards |
|---|
| MSDS | External MSDS |
| EU classification | Corrosive ('C') |
| NFPA 704 | |
| R-phrases | , |
| S-phrases | , , , |
| 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)
|
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.
Uses
Agriculture
★ Correction of the
pH of acidic soils
★ As a
fungicide
★ As an
herbicide
Manufacturing and commercial chemical processes
KOH is a major industrial chemical because it is 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 (raises pH by neutralizing acids)
★ Making
polyethylene resins
★
Textile processing
★ As a
catalyst in reactions like the production of
biodiesel.
★ Manufacture of many cleaning products, such as:
★
★ Washing powders
★
★ Cleansers (for tubs, tile, etc)
★
★ Some
denture cleaners
★
★ Non-
phosphate detergents
★
★ Drain or pipe cleaners (clog dissolvers)
★ Manufacture of
alkaline batteries, which use an aqueous solution of KOH as an electrolyte. Thus, potassium hydroxide helps to power flashlights, smoke detectors, and other battery-powered household items.
★ As an
anisotropic etchant of
silicon, exposing
octahedral planes. This technique can create pyramids and regularly-shaped etch pits for uses such as
microelectromechanical systems.
Medicine (human and veterinary)
★
KOH test (to diagnose
fungal infections)
★
Whiff test (to diagnose
bacterial vaginosis)
★
wart and
cuticle solvent
★ (''
veterinary medicine'') disbudding calves horns; dissolving scales and hair
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
★ Thickening
ice cream
★ Soaking of
olives to soften them and neutralize natural acids
★ Glazing of
pretzels and
German lye rolls before baking to make them crisp.
★ Soaking of
cod 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.
★ Making of
hominy, which is dried
maize (corn) kernels reconstituted by soaking in lye.
See also
★
Soda lime
External links
★
Newscientist article dn10104
★
MSDS from JTBaker
★ Reheis
[1]
★
Making lye from ashes