The easiest and fastest way - a direct reaction of potassium metal with water:
2k + 2H2O + H2 = 2KOH But it is not safe!The fact that potassium reacts with water very rapidly, much more active solution.That is why some teachers in chemistry classes the students were forced to learn a poem: "If you want to be a freak, throw more potassium in the water!".
Therefore it is better to obtain potassium hydroxide is more complex, but in a safe way: a mixture of boiling solution of potash (potassium carbonate) and slaked lime (calcium hydroxide).This reaction is thus:
K2CO3 + Ca (OH) 2 + 2KOH = SaSO3Obrazuyuschiysya calcium carbonate precipitates, the solution containing potassium hydroxide and filtered.
You can get this product and the reaction of its oxide with water:
K2O + H2O = 2KOH
In industry, the main method of producing potassium hydroxide - electrolysis of its salts, mainlychloride.Currently, there are three basic ways of electrolysis: mercury, that is, using a liquid mercury cathode, diaphragm and membrane.
first (mercury) method is the easiest and produces the most pure product, but it is extremely dangerous to the health of people employed in manufacturing, and the environment, because mercury vapor is highly toxic.Therefore, get rid of it, going to more complex, but also more secure methods.