Potassium hydroxide

General
Surname	Potassium hydroxide
Molecular formula	KOH
Brief description	colorless solution
External identifiers / databases
CAS number 1310-58-3 ( potassium hydroxide ) Wikidata Q1722251
properties
Molar mass	56.11 g · mol -1
Physical state	liquid
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 290-302-314 P: 280-301 + 330 + 331-305 + 351 + 338-308 + 310
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Potash lye is the common name for a strongly alkaline, caustic, aqueous solution of potassium hydroxide . Concentrated caustic potash etches glass to a small extent. The density of a 50% solution is at 15 ° C 1.539 g / cm ³ .

Manufacturing and transportation

Technical potassium hydroxide solution contains around 50% potassium hydroxide and is produced by electrolysis ( chlor-alkali electrolysis ) of potassium chloride solutions. Technical potassium hydroxide is usually transported in iron barrels or tank wagons.

use

Large quantities of potassium hydroxide are used in the chemical industry to produce potassium soap and colorants .

An important application is the use as an electrolyte (usually 20% solution) in unsealed nickel-cadmium batteries or nickel-iron batteries for stationary and mobile applications (e.g. UPS , emergency lighting , electric vehicles , etc.).

Like other alkalis , potassium hydroxide neutralizes acids of all kinds, producing potassium salts in each case. For example, potassium hydroxide (KOH) reacts with hydrochloric acid (HCl _aq ) to form water and potassium chloride . Because of its higher price, caustic potash is used to a lesser extent than caustic soda for wastewater neutralization .

In the laboratory, potassium hydroxide can be used to remove carbon dioxide from gas mixtures, as it reacts with the dissolved potassium hydroxide to form potassium carbonate :

${\displaystyle \mathrm {2\,KOH_{(aq)}+CO_{2\,(g)}\rightarrow K_{2}CO_{3\,(aq)}+H_{2}O_{(l)}} }$

(aq = aqueous solution )

Determination of salary

The potassium hydroxide content of potassium hydroxide solution is determined by titration with an acid using methyl orange as an indicator or by measuring the density .

Individual evidence

1. ↑ ^{a b c} Max Arnold, G. Christ, K. Dietrich, Ed. Gildmeister, P. Janzen, C. Scriba, B. Fischer, C. Hartwich: Hager's Handbook of Pharmaceutical Practice for Pharmacists, Doctors, Druggists and Medicinal Officials Second Volume . Springer-Verlag, 2013, ISBN 978-3-642-50682-6 , pp. 172 ( limited preview in Google Book search).
2. ↑ ^{a b} Entry on potassium hydroxide in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
3. ↑ Entry on Potassium hydroxide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ ^{a b} Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 3: H-L. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1983, ISBN 3-440-04513-7 , p. 2008.
5. ^ ^{A b} Brockhaus ABC Chemie , VEB FA Brockhaus Verlag, Leipzig 1965, pp. 612–613.