Magnesium hydroxide, characteristics, properties and production, chemical reactions

Magnesium hydroxide, characteristics, properties and production, and chemical reactions.

 

 

Magnesium hydroxide is an inorganic substance has the chemical formula Mg(OH)2.

 

Brief description of the magnesium hydroxide

Physical properties of magnesium hydroxide

Obtaining magnesium hydroxide

Chemical properties of magnesium hydroxide

Chemical reaction of magnesium hydroxide

The application and use of magnesium hydroxide

 



Brief description of the magnesium hydroxide:

Magnesium hydroxide is an inorganic substance of white color.

The chemical formula of magnesium hydroxide Mg(OH)2.

Practically insoluble in water. Is a weak basis, even a tiny part of it, indissoluble in water, said solution of alkaline reaction.

Absorbs carbon dioxide and water from air to form basic magnesium carbonate.

Found in nature as the mineral brucite.

 


Physical properties of magnesium hydroxide:

Parameter name: Value:
Chemical formula Mg(OH)2
Synonyms and foreign language names potassium hydroxide (eng.)

magnesium hydroxide (eng.)

brucite (Rus.)

The type of substance. inorganic
Appearance a colorless trigonal crystals
Color white
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 2344,6
Density (state of matter – solid, at 20 °C) g/cm3 2,3446
Decomposition temperature, °C 350
Molar mass, g/mol Of 58.35

* Note:

— no data.

 

Obtaining magnesium hydroxide:

Magnesium hydroxide is obtained by the following chemical reactions:

1. as a result of interaction of magnesium metal with water vapor:

Mg + 2H2O → Mg(OH)2 + H2.

2. as a result of interaction of magnesium oxide and water:

MgO + H2O → Mg(OH)2 (t = 100-125 °C).

3. the interaction of soluble salts with alkali:

MgCl2 + 2NaOH → Mg(OH)2 + 2NaCl,

Mg(NO3)2 + 2KOH → Mg(OH)2 + 2KNO3.

The magnesium hydroxide precipitates as sludge.

4. the interaction of magnesium chloride with calcined dolomite:

MgCl2 + CaO·MgO + 2H2O → 2Mg(OH)2 + CaCl2.

The magnesium hydroxide precipitates as sludge.

 

Chemical properties of magnesium hydroxide. Chemical reaction of magnesium hydroxide:

Magnesium hydroxide is the primary basis, i.e., has as main properties.

Magnesium hydroxide – slightly soluble weak base.

Chemical properties of magnesium hydroxide are similar to the properties of the hydroxides of the other major metals. So it is characterized by the following chemical reactions:

1. the reaction of magnesium hydroxide with sodium hydroxide:

Mg(OH)2 + 2NaOH → Na2[Mg(OH)4] (t = 100 °C).

The reaction produces sodium tetrahydrochromate. In the course of the reaction is a saturated solution of sodium hydroxide.

2. the reaction of magnesium hydroxide with carbonic acid:

Mg(OH)2 + Н2СО3 → MgCO3 + 2H2O.

The reaction produces magnesium carbonate and water.

3. the reaction of magnesium hydroxide with phosphoric acid:

Mg(OH)2 + 2H3PO4 → Mg(H2PO4)2 + H2O

Mg(OH)2 + H3PO4 → MgHPO4 + 2H2O

3Mg(OH)2 + 2H3PO4 → Mg3(PO4)2 + 6H2O.

As a result of reaction formed in the first case, digidrogenfosfat magnesium and water, the second gidrogenfosfat magnesium and water, a magnesium orthophosphate and water.

4. the reaction of magnesium hydroxide with nitric acid:

Mg(OH)2 + 2HNO3 → Mg(NO3)2 + 2H2O.

The reaction produces magnesium nitrate and water.

Similar are the reactions of magnesium hydroxide and other acids.

5. the reaction of magnesium hydroxide with hydrogen fluoride:

Mg(OH)2 + 2HF → MgF2 + 2H2O.

The reaction produces magnesium fluoride and water.

6. the reaction of magnesium hydroxide with bromovalerate:

Mg(OH)2 + 2HBr → MgBr2 + 2H2O.

In the reaction, the formed magnesium bromide and water.

7. the reaction of magnesium hydroxide with yodovidona:

Mg(OH)2 + 2HI → MgI2 + 2H2O.

The reaction produces iodide of magnesium and water.

8. the reaction of thermal decomposition of magnesium hydroxide:

Mg(OH)2 → MgO + H2O (t = 350 °C).

In the reaction, the formed magnesium oxide and water.

9. the reaction of magnesium hydroxide with hydrogen peroxide:

H2O2 + Mg(OH)2 → MgO2 + 2H2O (t < 20 °C).

In the reaction, the formed peroxide of magnesium and water. In the course of the reaction is a concentrated solution of peroxide of hydrogen.

10. the reaction of magnesium hydroxide with sulfur dioxide:

Mg(OH)2 + SO3 → MgSO4 + 2H2O.

The reaction produces magnesium sulfate and water.

11. the reaction of magnesium hydroxide with carbon dioxide:

Mg(OH)2 + 2CO2 → Mg(HCO3)2.

The reaction forms a bicarbonate of magnesium. During the reaction the hydroxide of magnesium is used in suspension.

12. the reaction of magnesium hydroxide with carbon dioxide:

Mg(OH)2 + 2N2O5 → Mg(NO3)2 + 2HNO3 (t = 40-60 °C).

The reaction produces magnesium nitrate and nitric acid.

 

The application and use of magnesium hydroxide:

Magnesium hydroxide is used in water treatment (as a flocculant), in detergents (as a Supplement), as filler in toothpaste, for refining sugar, as a food additive (Е528).

 

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