What is Calcium Hydroxide? 20, What is calcium hydroxide?

Calcium hydroxide (calciumhydroxide) is an inorganic compound with the chemical formula Ca(OH)2,

Calcium hydroxide (traditionally known as hydrated lime) is an inorganic compound with the chemical formula Ca(OH)2.

It is a colorless crystal or white powder obtained by mixing or curing quicklime (calcium oxide) with water.

It goes by many names, including hydrated lime, caustic lime, lime for construction, hydrated lime, calcium, and pickled lime. Calcium hydroxide is used in many applications, including food preparation, where it has been identified as E number E526.

Lime water, also known as milk of lime, is the generic name for a calcium hydroxide saturated solution.

Calcium hydroxide has the universal properties of alkali. Its alkalinity or corrosiveness is weaker than sodium hydroxide, and it can be said to be a moderately strong alkali, and these properties determine that calcium hydroxide has a wide range of applications. It is used in agriculture to reduce soil acidity and improve soil structure, and it is obvious that sodium hydroxide is not possible in this case.

Pesticide Bordeaux liquid is prepared in a certain proportion with an aqueous solution of lime milk and copper sulfate. It is named after the city of Bordeaux, France, which was first used in 1885. This sky-blue, viscous suspension pesticide used for fruit trees and vegetables uses the copper element in it to eliminate pests and diseases.

Among them, it not only uses the property that calcium hydroxide can react with copper sulfate, but also uses the characteristics of calcium hydroxide slightly soluble in water to make the liquid viscous, which is conducive to the adhesion of the liquid medicine on the branches and leaves of plants. In addition, calcium hydroxide reacts with carbon dioxide in the air to form calcium carbonate that is insoluble in water, which is also conducive to the attachment of the liquid medicine to the surface of the plant for a period of time without being washed away by rain.

The reaction of calcium hydroxide and carbon dioxide occurs frequently in chemical laboratories, in industrial and agricultural production, and in nature. It is often used. The fact that lime mortar bricks and plastered walls is well known.

What is less known is that this reaction also occurs in the sugar industry: in the sugar production process, calcium hydroxide is used to neutralize the acid in the syrup, and then carbon dioxide is introduced to make the remaining calcium hydroxide into a precipitate and filtered out, so as to reduce the sour taste of sugar.

The reaction of calcium hydroxide solution and saturated sodium carbonate solution can produce sodium hydroxide:

Ca(OH)2 + Na2CO3 = 2NaOH + CaCO3 , this reaction can be used to prepare a small amount of caustic soda.

1. Calcium hydroxide is a white powdery solid. The chemical formula Ca(OH)2, commonly known as hydrated lime and slaked lime, is added to water, and it is in two layers, the upper layer of aqueous solution is called clarified lime water, and the lower layer of turbidity is called lime milk or lime slurry.

2. The upper layer of clear lime water can detect carbon dioxide, and the lower layer of turbid liquid lime milk is a building material. Calcium hydroxide is a white powdery solid that is slightly soluble in water.

3. Calcium hydroxide is a binary medium strong alkali (calcium hydroxide is considered a strong alkali in middle school, but in fact it cannot be completely ionized in water, so it is considered a medium and strong alkali in college textbooks), which has the general properties of alkali and has a corrosive effect on ** and fabrics. Calcium hydroxide has a wide range of applications in industry. It is commonly used as a building material, and is also used as a fungicide and chemical raw material, etc.

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Differences: Different in nature, different in meaning.

First, the meaning is different:

Calcium oxide is a metal oxide (commonly known as "quicklime"), and calcium hydroxide is a relatively alkaline alkali (commonly known as "slaked lime").

Second, the nature is different:

Calcium oxide is called quicklime, alkaline oxide, and reacts with water to form calcium hydroxide called hydrated lime, which is exothermic by reaction. Quicklime has strong water absorption and can be used as a desiccant, and hydrated lime is used in decorative coatings, binders, etc. (commonly known as big white for powder walls). After brushing on the wall, it will react with carbon dioxide in the air to form calcium carbonate, which has strength.

1. It can be used as a filler, for example: a filler for epoxy adhesives;

2. It is used as an analytical reagent, a carbon dioxide absorber in gas analysis, a spectral analysis reagent, a high-purity reagent for epitaxy and diffusion processes in semiconductor production, and a laboratory ammonia drying and alcohol dehydration.

3. Used as raw materials, it can be used to manufacture calcium carbide, soda ash, bleaching powder, etc., and is also used for tanning, wastewater purification, calcium hydroxide and various calcium compounds;

4. It can be used as a flux for building materials, metallurgical flux, cement quick-setting agent, and phosphor;

5. Used as vegetable oil decolorizing agent, drug carrier, soil amendment and calcium fertilizer;

Calcium oxide and calcium hydroxide are important chemical raw materials, which are almost the same from the outside, but through application and comparison, you will find the difference between the two.

1. All natural rocks with calcium carbonate as the main component can be used to produce lime. To speed up decomposition, calcination temperatures are usually high. Lime often contains under-flint lime and over-flipped lime. The calcium carbonate in the o-flint lime partially decomposes and lacks cohesion when used.

2. The main component of lime is calcium oxide, white solid, refractory and insoluble. The high content of limestone is calcined to more than 900 degrees in a ventilated lime kiln. It reacts with water and absorbs moisture from moist air, that is, calcium hydroxide.

3. Its saturated solution is called lime water, which is alkaline and absorbs carbon dioxide in the air to form calcium carbonate precipitation.

4. In the lime slurry formed after lime curing, the lime particles form a calcium hydroxide colloidal structure, with fine particles and a large specific surface area, and its surface adsorbs a thick layer of water film, which can adsorb a large amount of water, so it has a strong ability to retain water, that is, good water retention. The properties between them are different, the composition is different, and the application environment is not the same, calcium hydroxide is generated by calcium oxide and water, and the two can not be mixed at ordinary times, and away from the humid environment.

Calcium hydroxideThe colloquial name isHydrated lime, slaked lime

Calcium hydroxide is a fine white powder at room temperature, slightly soluble in water, and its clear aqueous solution is commonly known as clarified lime water.

An emulsion suspension composed of water is called lime milk, and its solubility.

Decreases as the temperature increases. It is soluble in alcohol, soluble in ammonium salts and glycerol.

It can react with acid to generate the corresponding calcium salt, which is decomposed into calcium oxide and water at 580 hours.

Main applications:1. Agriculture. 1. Reduce soil acidity.

2. Improve soil structure.

3. Bordeaux liquid made of it.

It is used on fruit trees and vegetables to eliminate pests and diseases.

2. Life. Lime mortar can be used for bricklaying and plastering walls.

3. Industry. 1. Reduce the concentration of the solution and facilitate the decomposition of crystal seeds.

2. Further desiliconization of sodium aluminate solution.

3. It is convenient for red mud separation.

4. The mega key is conducive to the operation of the stable settlement tank.

The above content reference: Encyclopedia - calcium hydroxide.

Calcium hydroxideCommonly known as hydrated lime.

or slaked lime. Calcium hydroxide is an inorganic compound with the chemical formula Ca(OH)2, commonly known as hydrated lime or slaked lime. It is a white powdery solid, after adding water, it is divided into two layers, and the upper layer of aqueous solution is called clarified lime water.

The lower suspension is called lime milk or lime slurry. The supernatant clarified lime water can be used to test for carbon dioxide.

The lower layer of cloudy liquid lime milk is a building material. Calcium hydroxide is a strong alkali, which has the ability to kill bacteria and antiseptic, and has a corrosive effect on ** and fabrics.