Potassium hydroxide, characteristics, properties and production, chemical reactions
Potassium hydroxide, characteristics, properties and production, and chemical reactions.
Potassium hydroxide is an inorganic substance has the chemical formula KOH.
Brief description of potassium hydroxide
Physical properties of potassium hydroxide
Chemical properties of potassium hydroxide
The chemical reaction of potassium hydroxide
The application and use of potassium hydroxide
Brief description of potassium hydroxide:
Potassium hydroxide is an inorganic substance of white color.
The chemical formula of potassium hydroxide CON.
Has high hygroscopicity, but less than that of sodium hydroxide. Actively absorbs water vapors from air.
Highly soluble in water, while releasing large amounts of thermal energy.
Potassium hydroxide – a caustic, toxic and corrosive substance. It refers to the substances of the second class of danger. So working with them requires caution. After contact with skin, mucous membranes and eyes are serious chemical burns.
Physical properties of potassium hydroxide:
| Parameter name: | Value: |
| Chemical formula | CON |
| Synonyms and foreign language names | potassium hydroxide (eng.)
caustic potash (Rus.) potassium hydroxide (Rus.) |
| The type of substance. | inorganic |
| Appearance | colorless monoclinic crystals |
| Color | white, colorless |
| Taste | —* |
| The smell | — |
| Aggregate state (at 20 °C and atmospheric pressure of 1 ATM.) | solid |
| Density (state of matter – solid, at 20 °C), kg/m3 | 2044-2120 |
| Density (state of matter – solid, at 20 °C) g/cm3 | 2,044-2,12 |
| Boiling point, °C | 1327 |
| Melting point, °C | 380-406 |
| Hygroscopicity | high water absorption |
| Molar mass, g/mol | 56,1056 |
* Note:
— no data.
Obtaining potassium hydroxide:
The potassium hydroxide on an industrial scale is obtained in the electrolysis of chloride of potassium with a solid asbestos cathode (diaphragm method production), with polymer cathode (membrane method of production), with a liquid mercury cathode (mercury method of production).
The main trend in the world production of potassium hydroxide in the last 10 years is the transition of manufacturers to the membrane method electrolysis.
Chemical properties of potassium hydroxide. The chemical reaction of potassium hydroxide:
Potassium hydroxide is a chemically active substance, a strong chemical base.
KOH aqueous solutions have a strong alkaline reaction.
Chemical properties of potassium hydroxide are similar to the properties of the hydroxides of other alkali metals. So it is characterized by the following chemical reactions:
1. the reaction of potassium hydroxide with sodium:
KOH + Na → NaOH + K (t = 380-450 °C).
The reaction formed sodium hydroxide , and potassium.
2. the reaction of potassium hydroxide with chlorine:
2KOH + Cl2 → KCl + KClO + H2O.
The reaction formed potassium chloride, potassium hypochlorite and water. The potassium hydroxide as a starting material is used in the form of a cold concentrated solution.
3. the reaction of potassium hydroxide with iodine:
6KOH + 3H2 → 5KI + KIO3 + H2O (t = 80 °C).
The reaction formed potassium iodide, potassium Iodate and water. The potassium hydroxide as a starting material is used in the form of a hot concentrated solution.
4. the reaction of potassium hydroxide with aluminum and water:
2Al + 2KOH + 6H2O → 2K[Al(OH)4] + 3H2.
The reaction formed tetrahydroaluminate potassium and hydrogen. The potassium hydroxide as a starting material is used in the form of a hot concentrated solution.
5. the reaction of potassium hydroxide with zinc and water:
Zn + 2KOH + 2H2O → K2[Zn(OH)4] + H2.
The reaction formed tetrahydrozoline sodium and hydrogen.
6. the reaction of potassium hydroxide with phosphoric acid:
H3PO4 + KOH → KH2PO4 + H2O.
The reaction formed digidrogenfosfat potassium and water. With this as starting materials are used: phosphoric acid is in the form of a concentrated solution of potassium hydroxide in dilute solution.
7. the reaction of potassium hydroxide with nitric acid:
KOH + HNO3 → KNO3 + H2O.
The reaction produces potassium nitrate and water. Thus nitric acid as a starting material is used in the form of a dilute solution.
Similar are the reactions of potassium hydroxide and other acids.
8. the reaction of potassium hydroxide with hydrogen sulfide:
H2S + KOH → KHS + H2O.
The reaction formed potassium hydrosulfide and water. The potassium hydroxide as a starting material is used in the form of a dilute solution.
9. the reaction of potassium hydroxide with hydrogen fluoride:
HF + KOH → KF + H2O,
2HF + KOH → KHF2 + H2O.
As a result of reaction formed in the first case, the potassium fluoride and water, the second hydrofloric potassium and water. The potassium hydroxide and hydrogen fluoride in the first case as initial substance are used in the form of dilute solution, in the second case, potassium hydroxide and hydrogen fluoride are used in the form in the form of a concentrated solution.
10. the reaction of potassium hydroxide with bromovalerate:
HBr + KOH → KBr + H2O.
The reaction formed potassium bromide and water.
11. the reaction of potassium hydroxide with yodovidona:
HI + KOH → KI + H2O.
The reaction formed potassium iodide and water.
12. the reaction of potassium hydroxide with aluminum oxide:
Al2O3 + 2KOH → 2KAlO2 + H2O (t = 900-1100 °C).
Aluminium oxide is an amphoteric oxide. The reaction formed potassium aluminate and water. The reaction proceeds during the sintering of the starting materials.
13. the reaction of potassium hydroxide with aluminum oxide and water:
Al2O3 + 2KOH + 3H2O → 2K[Al(OH)4].
Aluminium oxide is an amphoteric oxide. The reaction formed potassium tetrahydroaluminate. The potassium hydroxide as a starting material is used in the form of a hot concentrated solution.
14. the reaction of potassium hydroxide with carbon dioxide (carbon dioxide):
KOH + CO2 → KHCO3,
2CO3 + KOH → KCO3 + H2O.
Carbon dioxide is an acidic oxide. As a result of reaction formed in the case of bicarbonate of potassium, in the latter case, potassium carbonate and water. The reaction in the first case occurs in ethanol.
15. the reaction of potassium hydroxide with sulfur dioxide:
SO2 + KOH → KHSO3,
2SO3 + KOH → K2SO3 + H2O.
Sulfur dioxide is an acidic oxide. As a result of reaction formed in the first case, the potassium hydrogen sulphite, in the second case, potassium sulfate and water. The reaction in the first case occurs in ethanol.
16. the reaction of potassium hydroxide with silica:
4KOH + 2SiO2 → K2SiO3 + K2Si4O5 + 2H2O (t = 900-1000 °C),
6KOH + 5SiO2 → K4SiO4 + K2Si4O9 + 3H2O.
As a result of reaction formed in the first case, the metasilicate potassium metatheatrical potassium and water, that’s the second case, the orthosilicate potassium tetrasilicate potassium and water. The potassium hydroxide as a starting material is used in the second case, in the form of a concentrated solution.
17. the reaction of potassium hydroxide with aluminium hydroxide:
Al(OH)3 + KOH → KAlO2 + 2H2O (t = 1000 °C),
Al(OH)3 + KOH → K[Al(OH)4].
Aluminium hydroxide is an amphoteric base. As a result of reaction formed in the first case, a potassium aluminate and water in the second case – tetrahydroaluminate sodium. The potassium hydroxide as a starting material is used in the second case, in the form of a concentrated solution.
18. the reaction of potassium hydroxide with zinc hydroxide:
Zn(OH)2 + 2KOH → K2[Zn(OH)4].
Zinc hydroxide is an amphoteric base. The reaction formed potassium tetrahydrozoline.
19. the reaction of potassium hydroxide with iron sulfate:
FeSO4 + 2KOH → Fe(OH)2 + K2SO4.
In the reaction, the formed hydroxide iron and potassium sulphate.
20. the reaction of potassium hydroxide with copper chloride:
CuCl2 + 2KOH → Cu(OH)2 + 2KCl.
In the reaction, the formed hydroxide of copper and chloride of potassium.
21. the reaction of potassium hydroxide with lead nitrate:
Pb(NO3)2 + 2KOH → Pb(OH)2 + 2KNO3.
In the reaction, the formed hydroxide of lead and nitrate of potassium.
22. the reaction of potassium hydroxide with aluminum chloride:
AlCl3 + 3KOH → Al(OH)3 + 3KCl.
In the reaction, the formed hydroxide of aluminium and chloride of potassium.
Similar are the reactions of potassium hydroxide and other salts.
The application and use of potassium hydroxide:
Potassium hydroxide is used in many industries and for domestic purposes:
in the pulp and paper industry – in the manufacture of paper, cardboard, synthetic fibers, wood-fiber boards;
for the saponification of fats in the manufacture of soap, shampoo and other detergents;
– in chemical and petrochemical industries as a versatile chemical compound;
– for the production of biodiesel fuel – derived from vegetable oils and used to replace conventional diesel fuel;
– in food industry: for washing and cleaning fruit and vegetables from the skin, as acidity regulator. Was in dietary Supplement E-525;
– in alkaline (alkaline) batteries – the electrolyte;
– in photography.
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