Calcium chloride is an inorganic compound. Its chemical formula is \({\rm{CaC}}{{\rm{l}}_2}\). It is a white crystalline salt. It is also known as anhydrous calcium chloride or calcium dichloride. It is an alkaline earth metal halide. It naturally occurs as a water-soluble sedimentary mineral deposit, sinjarite (dehydrate form) and antarcticite (hexahydrate form). In this article, we will discuss more details about Calcium Chloride Formula, and its other properties.

Calcium Chloride (CaCl₂)

The chemical formula of calcium chloride is \({\rm{CaC}}{{\rm{l}}_2}\). Calcium chloride is an ionic compound. It contains calcium \(\left( {{\rm{C}}{{\rm{a}}^{2 + }}} \right)\) and chloride \(({\rm{C}}{{\rm{l}}^ – })\) ions.

Formation of Calcium Chloride (CaCl₂)

The atomic number of calcium is \(20\). It has two electrons in its outermost shell. The atomic number of chlorine is \(17\). Hence, it will have seven electrons in its outermost shell. That is, calcium can donate two electrons to attain a stable configuration and a chlorine atom needs one more electron to complete its octet.

Therefore, during the formation of calcium chloride, the calcium atom donates its two outermost electrons to two chlorine atoms (one electron each for one chlorine atom). As a result, an ionic bond is formed between calcium and chlorine atoms. That is,

Calcium chloride can also be represented as,

The molar mass of calcium chloride is approximately equal to \(110.98\;{\rm{g}}/{\rm{mol}}\).

Preparation of Calcium Chloride (CaCl₂)

Calcium chloride can be prepared using the following methods:

1. Calcium chloride is produced as a major by-product during the manufacture of sodium carbonate (washing soda) using the Solvay process. That is, calcium chloride and sodium carbonate (washing soda) are produced when limestone (calcium carbonate) is reacted with sodium chloride solution. The net chemical equation for the reaction can be given as,

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

2. Calcium chloride is also produced when calcium carbonate (limestone) reacts with hydrochloric acid. The chemical equation for the reaction can be given as,

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

3. Calcium chloride can also be produced by the concentration and purification of naturally occurring brine extracted from salt lakes and salt deposits.

Properties of Calcium Chloride (CaCl₂)

Let us discuss the physical and chemical properties of calcium chloride.

Physical Properties of Calcium Chloride (CaCl₂)

1. Calcium chloride appears as a white powder. It is an odourless compound.
2. It is hygroscopic in nature. That is, it has a greater tendency to absorb the moisture from air.
3. It has comparatively high melting point \((~1045 – 1048\;{\rm{K}})\) and boiling point \((~2208\;{\rm{K}})\).
4. Calcium chloride is highly soluble in water. It is soluble even in acetic acid and alcohols. It is insoluble in liquid \({\rm{N}}{{\rm{H}}_3}\) and ethyl acetate.
5. The density of calcium chloride \(\left( {{\rm{CaC}}{{\rm{l}}_2}} \right)\) is \(2.15\;{\rm{g}}/{\rm{c}}{{\rm{m}}^3}\).

Chemical properties of Calcium chloride (CaCl₂)

1. Calcium chloride, when dissolved in water produces chloride ion and metal aquo complex \({\left[ {{\rm{Ca}}{{\left( {{{\rm{H}}_2}{\rm{O}}} \right)}_6}} \right]^{2 + }}\). Hence, this solution of calcium chloride acts as a source of calcium and chloride ions.
2. The electrolysis of molten calcium chloride produces calcium metal at the cathode and chlorine gas at the anode.
3. Reactions of Calcium Chloride \(\left( {{\rm{CaC}}{{\rm{l}}_2}} \right)\):

Reaction of Calcium Chloride with Sulphuric Acid

Calcium chloride reacts with sulphuric acid to give calcium sulphate and hydrogen chloride. That is,
\({\rm{CaC}}{{\rm{l}}_2} + {{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4} \to {\rm{CaS}}{{\rm{O}}_4} + 2{\rm{HCl}}\)

Reaction of Calcium Chloride with Sodium Carbonate

Calcium chloride reacts with sodium carbonate to form sodium chloride and calcium carbonate. That is,
\({\rm{N}}{{\rm{a}}_2}{\rm{C}}{{\rm{O}}_3}({\rm{aq}}) + {\rm{CaC}}{{\rm{l}}_2}({\rm{aq}}) \to {\rm{CaC}}{{\rm{O}}_3}(\;{\rm{s}}) + 2{\rm{NaCl}}({\rm{ag}})\)

Reaction of Calcium Chloride with Sodium Hydroxide

Calcium chloride reacts with sodium hydroxide to form calcium hydroxide and sodium chloride. That is,
\({\rm{CaC}}{{\rm{l}}_2} + {\rm{NaOH}} \to {\rm{Ca}}{({\rm{OH}})_2} + {\rm{NaCl}}\)

Reaction of Calcium Chloride with Sodium Sulphate

Calcium chloride reacts with sodium sulphate to form calcium sulphate and sodium chloride. That is,
\({\rm{CaC}}{{\rm{l}}_2} + {\rm{N}}{{\rm{a}}_2}{\rm{S}}{{\rm{O}}_4} \to {\rm{CaS}}{{\rm{O}}_4} + 2{\rm{NaCl}}\)

Uses of Calcium Chloride (CaCl₂)

Calcium chloride has got many uses. They include:

1. Calcium chloride is a hygroscopic substance. That is, it has a strong tendency to absorb moisture from the air on exposure. Because of this property, calcium chloride is used majorly as a drying agent.
2. In sports drinks and other beverages, it is used as an electrolyte.
3. It is used to flavor pickles because of its extremely salty taste.
4. Calcium chloride can be used to prevent ice-formation by depressing thezing point of water.
5. It is used for road surfacing. It also helps in road dust control.
6. It is used as an additive in fire extinguishers and plastics.
7. Calcium chloride can be used as flux in Davy process which is used for the industrial preparation of the metal sodium.
8. It is used in the manufacture of activated charcoal.
9. It is used in self heating cans and heating pads.
10. In fabric softening, calcium chloride is used as a thinner.
11. It is used to increase the density of solid brines in oil industry.
12. It is used in the production of ceramic slipware.
13. Calcium chloride dissolved in ethyl alcohol is used as a sterilant for male animals.
14. It is used in cheese making.
15. In medicines, it is used to treat the symptoms of Arrhythmias, Hypocalcemia, etc.

Summary

Calcium chloride is an alkaline earth metal halide. Its chemical formula is \({\rm{CaC}}{{\rm{l}}_2}\). It is a highly hygroscopic substance due to which it is most widely used as a drying agent. It is obtained as a by-product during the production of sodium carbonate using the Solvay process. The other preparation methods, the physical and chemical properties and their several uses are detailed in this article.

FAQs on Calcium Chloride (CaCl₂)

The most commonly asked questions about calcium chloride formula are answered here:

Q.1. What is the formula for calcium chloride? Ans: Calcium chloride is an inorganic compound with the chemical formula \({\rm{CaC}}{{\rm{l}}_2}\).

Q.2. How is chloride of lime chemically different from calcium chloride? Ans: Chloride of lime is chemically an alkaline compound called as calcium oxychloride \(\left( {{\rm{CaOC}}{{\rm{l}}_2}} \right)\). It is commonly known as bleaching powder. But, calcium chloride is chemically a neutral compound called as calcium chloride \(\left( {{\rm{CaC}}{{\rm{l}}_2}} \right)\).

Q.3. What is calcium chloride commonly used for? Ans: Calcium chloride is commonly used as an electrolyte in sports and other bottled beverages. It prevents one from getting dehydrated. It has some other uses also. They include its use as a drying agent, in fire extinguishers and plastics, in ceramic slipware, sterilant, etc.

Q.4. Is calcium chloride harmful to the human body? Ans: In trace amounts in foods and other beverages, it is safe to consume. The direct swallowing of calcium chloride can cause the mouth and throat to burn, vomiting, stomach pain, etc. It has several other uses also.

Q.5. Is it safe to drink water with calcium chloride in it? Ans: Yes, it is safe to drink water that contain calcium chloride in permitted amounts. It acts an electrolyte, and it keeps one from getting dehydrated.

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