Ca (OH) 2 - is calcium hydroxide (from the Latin Calcium hydroxide), it is fairly common chemical.It is considered inherently strong base.It represents melkokrupinchaty yellowish powder or colorless crystals.Is degradable by heating, resulting in calcium oxide is released.It is poorly soluble in water.An aqueous solution of calcium hydroxide on their chemical properties is an average basis.In the presence of metals may release hydrogen, which is recognized by explosive gas.
Calcium hydroxide when entering the body through the mouth or by inhalation of an aerosol can be absorbed into the tissues and accumulate in them.At normal room temperature, 20-22 degrees this substance practically does not evaporate, but spraying of the particles can be hazardous to health.Getting on the skin, the respiratory tract and mucous membranes of the eyes, the calcium hydroxide is an irritant, even corrosive.Prolonged contact with the skin can cause dermatitis.It can also affect lung tissue at constant exposure to the particles of calcium hydroxide.
This chemical compound has many trivial names such as hydrated lime (it is produced by quenching the calcium oxide with plain water), lime water (a clear aqueous solution).Other names: pushonka (calcium hydroxide in the form of a dry powder), and milk of lime (saturated aqueous slurry).Often, lime or lime is called as calcium oxide.
calcium hydroxide, chemical properties which are considered aggressive with respect to other substances, prepared by slaking, i.e., by reaction (chemical reaction) of calcium oxide and water.Schematically, the reaction is as follows:
CaO + H2O = Ca (OH) 2
to obtain an aqueous solution of alkaline reaction is characteristic of the medium.Like all typical hydroxides, calcium hydroxide is reacted with: 1.
inorganic acids to form calcium salts
typical H2SO4+ Ca (OH) 2 = CaSO4 + 2H2O
2. carbon dioxide, which is dissolved in water, so water solutionvery quickly in the air cloudy, with a white insoluble precipitate - calcium carbonate
CO2 + Ca (OH) 2 = CaCO3 + H2O
3. carbon monoxide at elevated temperatures up to 400 degrees Celsius
CO (t °) + Ca(OH) 2 = CaCO3 + H2
4. salts, as a result of a white precipitate - calcium sulfate
Na2SO3 + Ca (OH) 2 = CaSO3 + 2NaOH
use of calcium hydroxide is very popular.Surely, everyone knows that the walls treated with lime facilities, tree trunks, as well as use it as a component of the building mortar.The use of calcium hydroxide in the building has been known since ancient times.And now it is included in the plaster of his produce silicate brick and concrete, the compositions of which are almost identical with mortar.The main difference is in the method of preparation of these same solutions.
calcium hydroxide is used to soften hard water, for the manufacture of bleach, lime inorganic fertilizers causticization of sodium carbonate, and potassium.Also this material is indispensable for tanning in the textile industry, in the preparation of various compounds of calcium as well as for neutralization of acidic solutions, and waste waters including.On the basis of obtained organic acids.
Calcium hydroxide has found its application in the food industry, where it is more known as a food additive E526, is used as a pH regulator, a hardener and a thickener.In the sugar industry it is used for leaching of molasses.
In laboratory experiments and demonstration lime water is an essential indicator of the detection of carbon dioxide in the course of chemical reactions.Milk of lime treated plants to fight diseases and pests.
