{{chembox
| Watchedfields = chynged
| verifiedrevid = 464361974
| Name = Potassium hydroxide
| ImageFile1 = Potassium hydroxide.jpg
| ImageSize1 = 200px
| ImageName1 = Pellets o potassium hydroxide
| ImageFile = Potassium-hydroxide-xtal-3D-vdW.png
| ImageName = Crystal structur o KOH
| ImageSize = 150px
| IUPACName = Potassium hydroxide
| OtherNames = Caustic potash, Potash lye, Potassia, Potassium hydrate
| Section1 = {{Chembox Identifiers
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = WZH3C48M4T
| InChI = 1/K.H2O/h;1H2/q+1;/p-1
| InChIKey = KWYUFKZDYYNOTN-REWHXWOFAT
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 32035
| SMILES = [K+].[OH-]
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/K.H2O/h;1H2/q+1;/p-1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = KWYUFKZDYYNOTN-UHFFFAOYSA-M
| CASNo = 1310-58-3
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 14797
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 14113
| RTECS = TT2100000
| UNNumber = 1813
| EINECS = 215-181-3
}}
| Section2 = {{Chembox Properties
| K=1|O=1|H=1
| Appearance = white solid, [[deliquescent]]
| Odor = odorless
| Density = 2.044 g/cm<sup>3</sup> (20 °C)<ref name=crc/><br> 2.12 g/cm<sup>3</sup> (25 °C)<ref name=chemister />
| Solubility = 85 g/100 g (-23.2 °C)<br> 97 g/100 mL (0 °C)<br> 121 g/100 mL (25 °C)<br> 138.3 g/100 mL (50 °C)<br> 162.9 g/100 mL (100 °C)<ref name=crc>{{RubberBible86th|page=4-80}}</ref><ref name=sioc>{{cite book|last = Seidell|first = Atherton|last2 = Linke|first2 = William F.|year = 1952|title = Solubilities of Inorganic and Organic Compounds|publisher = Van Nostrand|url = [http://books.google.com/books?id=k2e5AAAAIAAJ Google Books]|accessdate = 2014-05-29}}</ref>
| SolubleOther = soluble in [[alcohol]], [[glycerol]] <br> insoluble in [[ether]], liquid [[ammonia]]
| Solubility2 = 55 g/100 g (28 °C)<ref name=chemister />
| Solvent2 = methanol
| MeltingPtC = 406 
| BoilingPtC = 1327
| pKa = 13.5 (0.1 M)
| RefractIndex = 1.409 (20 °C)
}}
| Section3 = {{Chembox Structure
| Coordination =
| CrystalStruct =rhombohedral
}}
| Section4 = {{Chembox Thermochemistry
|   DeltaHf = -425.8 kJ/mol<ref name=b1>{{cite book| author = Zumdahl, Steven S.|title =Chemical Principles 6th Ed.| url = https://archive.org/details/chemicalprincipl0000zumd_u9g0| publisher = Houghton Mifflin Company| year = 2009| isbn = 0-618-94690-X|page=A22}}</ref><ref name=chemister>http://chemister.ru/Database/properties-en.php?dbid=1&id=325</ref>
|   Entropy = 79.32 J/mol·K<ref name=b1 /><ref name=chemister />
|   DeltaGf = -380.2 kJ/mol<ref name=chemister />
|   HeatCapacity = 65.87 J/mol·K<ref name=chemister />
 }}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://www.inchem.org/documents/icsc/icsc/eics0357.htm ICSC 0357]
|   GHSPictograms = {{GHS05}}{{GHS07}}<ref name="sigma">{{Sigma-Aldrich|id=757551|name=Potassium hydroxide|accessdate=2014-05-18}}</ref>
| GHSSignalWord = Danger
|   HPhrases = {{H-phrases|302|314}}<ref name="sigma" />
|   PPhrases = {{P-phrases|280|305+351+338|310}}<ref name="sigma" />
| EUIndex = 019-002-00-8
| EUClass = {{Hazchem C}} {{Hazchem Xn}}
| RPhrases = {{R22}}, {{R35}}
| SPhrases = {{S1/2}}, {{S26}}, {{S36/37/39}}, {{S45}}
| NFPA-H = 3
| NFPA-F = 0
| NFPA-R = 1
| NFPA-O = 
| FlashPt = Non-flammable
| LD50 = 273 mg/kg (oral, rat)<ref>http://chem.sis.nlm.nih.gov/chemidplus/rn/1310-58-3</ref>
}}
| Section8 = {{Chembox Related
| OtherAnions = [[Potassium hydrosulfide]]<br/>[[Potassium amide]]
| OtherCations = [[Lithium hydroxide]]<br/>[[Sodium hydroxide]]<br/>[[Rubidium hydroxide]]<br/>[[Caesium hydroxide]]
| OtherCpds = [[Potassium oxide]]
}}
}}
'''Potassium hydroxide''' is an [[inorganic compoond]] wi the formula [[potassium|K]][[hydroxide|OH]], commonly cried '''caustic [[potash]]'''.