Aluminum hydroxide

The appearance of the aluminum hydroxide material is as follows. As a rule, this substance is white, gelatinous, although there are variants of presence in the crystalline or amorphous state. For example, in dried form it crystallizes into white crystals, which do not dissolve either in acids or in alkalis.

Aluminum hydroxide can also be represented by a fine-grained white powder. The presence of pink and gray shades is acceptable.

The chemical formula of the compound is Al (OH) 3. The combination of aluminum oxide and water forms aluminum hydroxide , whose chemical properties are also largely determined by the elements that make up its composition. This compound is prepared by reacting the aluminum salt and dilute alkali, while avoiding overabundance. The precipitate of aluminum hydroxide produced in this reaction can then react with acids.

Aluminum hydroxide reacts with an aqueous solution of rubidium hydroxide, an alloy of this substance, cesium hydroxide, cesium carbonate. In all cases, water is released.

Aluminum hydroxide has a molecular weight of 78.00, practically insoluble in water. The density of the substance is 3.97 g / cm3. Being an amphoteric substance, aluminum hydroxide reacts with acids, with the result that the reactions produce medium salts and release water. Upon entering into reactions with alkalis, complex salts - hydroxoaluminates, for example, K [Al (OH) 4 (H2O) 2] appear. Meta-aluminates are formed if aluminum hydroxide is alloyed with anhydrous alkalis.

Like all amphoteric substances, acid and basic properties simultaneously aluminum hydroxide shows when interacting with strong acids, as well as with alkalis. In these reactions, during the dissolution of the hydroxide in acids, the ions of the hydroxide itself are cleaved, and in the reaction with the alkali, the hydrogen ion is split off. To see this, you can, for example, carry out a reaction involving aluminum hydroxide, sodium hydroxide. To conduct it, it is necessary to fill in a small amount of sawdust in the test tube and pour a small amount of sodium hydroxide, not more than 3 milliliters. The tube should be tightly closed with a stopper, and begin a slow preheating. After this, fixing the tube to a tripod, it is necessary to assemble the isolated hydrogen into another tube, having preliminarily put it on the capillary fixture. After about a minute, the test tube should be removed from the capillary and brought to a flame. If pure hydrogen is collected in the test tube, the combustion will proceed smoothly, in the same case, if air gets into it, cotton will occur.

Aluminum hydroxide is obtained in laboratories in several ways:

- by reaction of interaction of aluminum salts and alkaline solutions;

- a way of decomposition of aluminum nitride under the influence of water;

- by passing carbon through a special hydro complex containing Al (OH) 4;

- the action of hydrate of ammonia on aluminum salts.

Industrial production is associated with bauxite processing. Technologies of influence on aluminate solutions by carbonates are also used.

Aluminum hydroxide is used in the manufacture of mineral fertilizers, cryolite, various medical and pharmacological preparations. In chemical production, the substance is used to produce aluminum fluoride and sulfur dioxide. Indispensable connection in the production of paper, plastics, paints and much more.

Medical use is due to the positive effects of drugs containing this element in the treatment of gastric disorders, increased acidity of the body, ulcer diseases.

When handling the substance, you should be careful not to inhale its vapors, as they cause severe damage to the lungs. Being a mild laxative, it is dangerous in large doses. When corrosion causes aluminosis.

The substance itself is quite safe, since it does not react with oxidants.