Per secoli la lisciva Ŕ stata il migliore detergente da bucato.
potash = obtained leaching the ash of burnt wood or tree leaves and evaporating the solution in a pot.
K2CO3 Potassium carbonate is the primary component of potash, because plants have little or no sodium content, and the rest of a plants' major mineral content consists of calcium salts of low water solubility.
Historically created by baking potash in a kiln to remove impurities.
K2O A contatto con l'acqua, reagisce violentemente formando KOH idrossido di potassio. Il composto Ŕ corrosivo e fortemente irritante.
KOH historically was made by boiling a solution of potash with slaked lime
K2CO3 + Ca(OH)2 → CaCO3 + 2 KOH
a metathesis reaction which caused CaCO3 to precipitate, leaving KOH in solution. Filtering off the precipitated CaCO3 and boiling down the solution gives KOH.
|SolubilitÓ in acqua|
|Ca(OH)2||74,1||1,7||g/l a 293 K|
|g/L (20 ░C)
g/L (100 ░C)
|KOH||56,1||1130||g/L (20 ░C)|
Potassium metal was first isolated in 1807 in England by Sir Humphry Davy, who derived it from caustic potash (KOH), by the use of electrolysis of the molten salt with the newly discovered voltaic pile. Potassium was the first metal that was isolated by electrolysis. Later in the same year, Davy reported extraction of the metal sodium from a mineral derivative (caustic soda, NaOH, or lye), not a plant salt, by a similar technique, demonstrating the elements, and thus the salts, to be different.
Hydrogen is liberated that burns with a pink/lilac flame, the flame color owing to burning potassium vapour. Strongly alkaline potassium hydroxide is formed in solution.
Se riscaldato a 512 ░C l'idrossido di calcio si decompone in ossido di calcio e acqua.
K2CO3 Potassium carbonate, Carbonato di potassio
CO32− +2 H2O ↔ HCO3− + H2O + OH− ↔ H2CO3 +2 OH−
H2CO3 +2 H2O ↔ HCO3− + H3O+ + H2O ↔ CO32− +2 H3O+