Magnesium Chloride Formula: Definition, Preparation, Properties

Magnesium chloride is an alkaline earth metal halide. It is an inorganic chemical compound with the formula \({\rm{MgC}}{{\rm{l}}_2}\). Magnesium chloride, \({\rm{MgC}}{{\rm{l}}_2}\) is an ionic compound. It contains magnesium \(\left( {{\rm{M}}{{\rm{g}}^{2 + }}} \right)\) ion and chloride ions \(\left( {{\rm{C}}{{\rm{l}}^ – }} \right)\).

 In this article, we are going to discuss about magnesium chloride formula, its preparation, properties and uses in detail.

Formation of Magnesium Chloride

 The atomic number of magnesium is \(12\). Therefore, it has two electrons in its outermost shell. Similarly, the atomic number of chlorine is \(17\). It has seven electrons in its outermost shell.

During the formation of magnesium chloride, the magnesium atom donates the two outermost electrons to two chlorine atoms (one electron each). As a result, an ionic or electrovalent bond is formed between the magnesium ion and chloride.

It can be represented as,

The molar mass of magnesium chloride, \({\rm{MgC}}{{\rm{l}}_2}\) is \(95.211\;{\rm{g}}/{\rm{mol}}\).

Preparation of Magnesium Chloride (MgCl₂)

Magnesium chloride is naturally found as the mineral bischofite. Hydrated magnesium chloride can be extracted from seawater or brine.

Magnesium chloride or the anhydrous magnesium chloride \({\rm{MgC}}{{\rm{l}}_2}\) can be prepared using the following methods:

1. Magnesium chloride is produced when the metal magnesium is reacted with hydrochloric acid. The chemical equation for the reaction can be given as,

\({\rm{Mg}} + 2{\rm{HCl}} \to {\rm{MgC}}{{\rm{l}}_2} + {{\rm{H}}_2}\)

2. Magnesium chloride is produced when magnesium carbonate reacts with hydrochloric acid. The chemical equation for the reaction can be given as,

\({\rm{MgC}}{{\rm{O}}_3} + 2{\rm{HCl}} \to {\rm{MgC}}{{\rm{l}}_2} + {\rm{C}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}}\)

3. During the Dow process (It is an electrolytic process used for the extraction of bromine from brine), magnesium chloride is regenerated as a result of the reaction between magnesium hydroxide and hydrochloric acid. The chemical equation for the reaction can be given as,

\({\rm{Mg}}{({\rm{OH}})_2} + 2{\rm{HCl}} \to {\rm{MgC}}{{\rm{l}}_2} + 2{{\rm{H}}_2}{\rm{O}}\)

4. Magnesium chloride can also be prepared by the reaction of magnesium hydroxide with ammonium chloride. The chemical equation for the reaction can be given as,

\({\rm{Mg}}{({\rm{OH}})_2} + 2{\rm{N}}{{\rm{H}}_4}{\rm{Cl}} \to {\rm{MgC}}{{\rm{l}}_2} + 2{\rm{N}}{{\rm{H}}_3} + 2{{\rm{H}}_2}{\rm{O}}\)

Properties of Magnesium Chloride (MgCl₂)

Let us discuss the physical and chemical properties of magnesium chloride \({\rm{MgC}}{{\rm{l}}_2}\).

Physical Properties of Magnesium Chloride (MgCl₂)

1. Magnesium chloride appears as a white to colourless crystalline solid.
2. It is readily soluble in water and ethanol, and is slightly soluble in acetone and pyridine.
3. Magnesium chloride is strongly deliquescent in nature. That is, it has the tendency to absorb moisture from the air. Hence, it becomes the hydrated form, \({\rm{MgC}}{{\rm{l}}_2} \cdot 6{{\rm{H}}_2}{\rm{O}}\) (magnesium chloride hexahydrate).
4. Since magnesium chloride is an ionic compound, magnesium chloride has a high melting \(\left( {987\;{\rm{K}}} \right)\) and boiling points \(\left( {1685\;{\rm{K}}} \right).\)
5. Aqueous solution or the molten form of magnesium chloride conducts electricity. This is because, magnesium chloride is an ionic compound. Therefore, in aqueous and molten states, it can release ions which are responsible for the conduction of electricity.

Chemical Properties Magnesium Chloride (MgCl₂)

Let us discuss the different reactions of magnesium chloride \({\rm{MgC}}{{\rm{l}}_2}.\)

Reactions of Magnesium Chloride (MgCl₂)

1. Magnesium chloride reacts with sodium hydroxide to form magnesium hydroxide and sodium chloride. The chemical equation for the reaction can be given as,

\({\rm{MgC}}{{\rm{l}}_2} + 2{\rm{NaOH}} \to {\rm{Mg}}{({\rm{OH}})_2} + 2{\rm{NaCl}}\)

2. Magnesium chloride reacts with sulphuric acid to form magnesium sulphate and hydrogen chloride gas. The chemical equation for the reaction can be given as,

\({\rm{MgC}}{{\rm{l}}_2} + {{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4} \to {\rm{MgS}}{{\rm{O}}_4} + 2{\rm{HCl}}\)

3. Magnesium chloride reacts with sodium carbonate forming magnesium carbonate and sodium chloride. The chemical equation for the reaction can be given as,

\({\rm{N}}{{\rm{a}}_2}{\rm{C}}{{\rm{O}}_3} + {\rm{MgC}}{{\rm{l}}_2} \to {\rm{MgC}}{{\rm{O}}_3} + 2{\rm{NaCl}}\)

4. Magnesium chloride reacts with aluminum phosphate to give magnesium phosphate and aluminum chloride. The chemical equation for the reaction can be given as,

\(2{\rm{AIP}}{{\rm{O}}_4} + 3{\rm{MgC}}{{\rm{l}}_2} \to {\rm{M}}{{\rm{g}}_3}{\left( {{\rm{P}}{{\rm{O}}_4}} \right)_2} + 2{\rm{AlC}}{{\rm{l}}_3}\)

5. Electrolysis of molten magnesium chloride, \({\rm{MgC}}{{\rm{l}}_2}\): When molten magnesium chloride is electrolyzed, the metallic magnesium is produced at the cathode (as a result of reduction reaction) and chlorine gas is released at the anode (as a result of oxidation reaction). That is,

Thus, magnesium chloride \({\rm{MgC}}{{\rm{l}}_2}\) is used as a precursor to the magnesium \(({\rm{Mg}})\) metal.

Uses of Magnesium Chloride (MgCl₂)

Magnesium chloride \({\rm{MgC}}{{\rm{l}}_2}\) has got many uses. They are:

1. Hydrated form of magnesium chloride can be used for the extraction of brine from seawater.
2. It is used as an industrial chemical for the preparation of magnesium metal.
3. It is used in the field of medicine as a source of magnesium ions.
4. It is used as a mineral supplement which is given for treating the deficiency of magnesium levels in the blood.
5. It is used for soil stabilization, dust control and wind erosion mitigation.
6. It is used for the de-icing of highways.
7. It is used as catalyst support.
8. It is used as a coagulant in the preparation of soy milk and tofu.
9. It is used to treat mineral deficiency in plants.
10. It is used in the textile industry, cement and paper manufacture.
11. Magnesium chloride is also used as a fireproofing and deicing agent.

Summary

Magnesium chloride is an inorganic chemical compound with the chemical formula \({\rm{MgC}}{{\rm{l}}_2}\). It is an ionic compound formed by the transfer of electrons between magnesium and chlorine atoms. It can be simply prepared by the action of magnesium metal with hydrochloric acid. In this article, we have learnt more about magnesium chloride. The formula, preparation methods, physical and chemical properties. Magnesium chloride has got many uses in different fields. They are also included in this article.

FAQs

Q.1. What is the formula for magnesium chloride?
Ans: Magnesium chloride is an inorganic chemical compound with the chemical formula \({\rm{MgC}}{{\rm{l}}_2}\). It is an ionic compound.

Q.2. Is magnesium chloride ionic or covalent?
Ans: Magnesium chloride is an ionic compound formed by the transfer of electrons between magnesium and chlorine atoms.

Q.3. What is magnesium chloride used for? 
Ans: Magnesium chloride has got many uses. It is used as an industrial chemical for the preparation of magnesium metal, used as a mineral supplement that is given for treating the deficiency of magnesium levels in the blood, is used as catalyst support, etc.

Q.4. What are the side effects of magnesium chloride?
Ans: The consumption of magnesium chloride more than the permitted value can cause health problems. Common side effects of magnesium chloride include hypothermia, respiratory depression, decreases blood pressure, sweating, etc.

Q.5. Is magnesium chloride soluble in water?
Ans: Magnesium chloride is readily soluble in water. It is soluble in ethanol too. But in acetone and pyridine, it is slightly soluble.

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