Potassium hydroxide (other names – caustic heat, potassium lye) has a chemical formula KON. Appearance – white or light-grayish scales, granules. Very hygroscopic substance, on air blurs quickly, "hackneyed". How to receive potassium hydroxide?
Instruction
1. The easiest and fast way – direct reaction of metal potassium with water: 2K + 2H2O = 2KOH + But it is unsafe H2! The fact is that potassium reacts with water extremely violently, is much more active than sodium. For this reason some teachers at lessons of chemistry forced pupils to learn the rhyme: "If you want to become a freak, throw rather a potassium into water!".
2. Therefore it is better to receive potassium hydroxide in more difficult, but safe way: having boiled potash solution mix (potassium carbonic) and extinguished lime (calcium hydroxide). This reaction takes place thus: K2CO3 + Sa (IT) 2 = 2KOH + SaSO3Obrazuyushchiysya the carbonate of calcium drops out in a deposit, the solution containing potassium hydroxide is filtered.
3. It is possible to receive this product and reaction of its oxide with water: K2O + H2O = 2KOH
4. In the industry the main way of receiving potassium hydroxide – electrolysis of its salts, mainly, chloride. Now, there are three main ways of this electrolysis: mercury, that is with use of the liquid mercury cathode, diaphragm and membrane.
5. The first (mercury) way the simplest also provides the cleanest product, but it constitutes exclusive health hazard of the people occupied in production and for the environment as vapors of mercury are very poisonous. Therefore get rid of it, passing to more difficult, but also safer methods.