Aluminum hydroxide, characteristics, properties and production, chemical reactions
Aluminum hydroxide, characteristics, properties and production, and chemical reactions.
Aluminum hydroxide is an inorganic substance and has chemical formula Al(OH)3.
Brief description of aluminum hydroxide
Modification of aluminium hydroxide
Physical properties of aluminum hydroxide
Receipt of aluminium hydroxide
Chemical properties of aluminium hydroxide
The chemical reaction of aluminum hydroxide
The application and use of aluminium hydroxide
Brief description of aluminium hydroxide:
Aluminum hydroxide is an inorganic substance of white color.
The chemical formula of aluminium hydroxide Al(OH)3.
Poorly soluble in water.
Has the ability to adsorb various substances.
Modification of aluminium hydroxide:
4 known crystalline modifications of hydroxide of aluminium: gibbsite, bayerite, doyleite and nordstrandite.
Gibbsite is indicated by γ-form of aluminum hydroxide and bayerite – α-form of the hydroxide of aluminium.
Gibbsite is the most chemically stable form of the hydroxide of aluminium.
Physical properties of aluminum hydroxide:
| Parameter name: | Value: |
| Chemical formula | Al(OH)3 |
| Synonyms and foreign language names for aluminum hydroxide α-shape | potassium hydroxide (eng.)
aluminum hydroxide α-form (English). bayerite (Rus.) |
| Synonyms and foreign language names for aluminum hydroxide to γ-shape | potassium hydroxide (eng.)
aluminium hydroxide (eng.) aluminum hydroxide (English). hydrargillite (English). gibbsite (Rus.) hydrargillite (Rus.) |
| The type of substance. | inorganic |
| Appearance of aluminum hydroxide α-shape | colorless monoclinic crystals |
| Appearance of aluminum hydroxide and γ-forms | white monoclinic crystals |
| Color | white, colorless |
| Taste | —* |
| The smell | — |
| Aggregate state (at 20 °C and atmospheric pressure of 1 ATM.) | solid |
| The density of aluminum hydroxide to the γ form (state of matter – solid, at 20 °C), kg/m3 | 2420 |
| The density of aluminum hydroxide to the γ form (state of matter – solid, at 20 °C) g/cm3 | 2,42 |
| Decomposition temperature of aluminum hydroxide α-shape, °C | 150 |
| Decomposition temperature of aluminum hydroxide and γ-forms, °C | 180 |
| Molar mass, g/mol | 78,004 |
* Note:
— no data.
Receipt of aluminium hydroxide:
Aluminium hydroxide is obtained by the following chemical reactions:
1. the interaction of aluminum chloride and sodium hydroxide:
AlCl3 + 3NaOH → Al(OH)3 + 3NaCl.
The aluminium hydroxide is precipitated in the form of a white gelatinous precipitate.
Aluminium hydroxide is also obtained at interaction of salts of aluminum with aqueous alkali, avoiding an excess.
2. the interaction of aluminum chloride, sodium carbonate and water:
2AlCl3 + 3Na2CO3 + 3H2O → 2Al(OH)3 + 3CO2 + 6NaCl.
The aluminium hydroxide is precipitated in the form of a white gelatinous precipitate.
Aluminium hydroxide is also obtained in the interaction of water-soluble salts of aluminum with carbonates of alkali metals.
Chemical properties of aluminium hydroxide. Chemical reaction of aluminium hydroxide:
Aluminium hydroxide has an amphoteric properties, i.e. has both basic and acidic properties.
Chemical properties of aluminium hydroxide are similar to the properties of amphoteric hydroxides of other metals. So it is characterized by the following chemical reactions:
1. the reaction of aluminium hydroxide with sodium hydroxide:
Al(OH)3 + NaOH → NaAlO2 + 2H2O (t = 1000 °C),
Al(OH)3 + 3NaOH → Na3[Al(OH)6],
Al(OH)3 + NaOH → Na[Al(OH)4].
As a result of reaction formed in the first case – aluminate of sodium and water, the second hexahydroxoantimonate sodium, in the third – tetrahydroaluminate sodium. In the third case, as the hydroxide of sodium is used a concentrated solution.
2. the reaction of aluminium hydroxide with potassium hydroxide:
Al(OH)3 + KOH → KAlO2 + 2H2O (t = 1000 °C),
Al(OH)3 + KOH → K[Al(OH)4].
As a result of reaction formed in the first case, a potassium aluminate and water, the second tetrahydroaluminate potassium. In the second case, as potassium hydroxide is used a concentrated solution.
3. the reaction of aluminium hydroxide with nitric acid:
Al(OH)3 + 3HNO3 → Al(NO3)3 + 3H2O.
The reaction produces aluminium nitrate and water.
Similarly, are the reaction of aluminum hydroxide and other acids.
4. the reaction of aluminum hydroxide with hydrogen fluoride:
Al(OH)3 + 3HF → AlF3 + 3H2O,
6HF + Al(OH)3 → H3[AlF6] + 3H2O.
As a result of reaction formed in the first case – aluminum fluoride and water, the second hexafluoroaluminate hydrogen and water. The fluoride in the first case as the initial substance used in the form of a solution.
5. the reaction of aluminum hydroxide with bromovalerate:
Al(OH)3 + 3HBr → AlBr3 + 3H2O.
The reaction produces aluminium bromide and water.
6. the reaction of aluminum hydroxide with yodovidona:
Al(OH)3 + 3HI → AlI3 + 3H2O.
The reaction of the iodide are formed of aluminum and water.
7. the reaction of thermal decomposition of aluminium hydroxide:
Al(OH)3 → AlO(OH) + H2O (t = 200 °C),
2Al(OH)3 → Al2O3 + 3H2O (t = 575 °C).
As a result of reaction formed in the first case, Metagalaxy aluminum and water, the second aluminium oxide and water.
8. the reaction of aluminum hydroxide and sodium carbonate:
2Al(OH)3 + Na2CO3 → 2NaAlO2 + CO2 + 3H2O.
The reaction produces sodium aluminate, carbon oxide (IV) and water.
10. the reaction of aluminum hydroxide and calcium hydroxide:
Ca(OH)2 + 2Al(OH)3 → Ca[Al(OH)4]2.
The reaction formed tetrahydroaluminate calcium.
The application and use of aluminium hydroxide:
Aluminum hydroxide is used in water purification (as adsorbing substance), in medicine, as a filler in toothpaste (as an abrasive material), plastics and plastics (as a retardant).
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