Calcium Chloride - CaCl₂

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What is CaCl2?

CaCl2 can be said as an ionic compound having a chemical name, Calcium Chloride. We can also call it either Calcium dichloride or Calcium chloride anhydrous.


It is an ionic compound composed of chlorine and calcium. It is a crystalline solid white in color at room temperature and is highly soluble in water, and hence it is hygroscopic in nature. It has a very high enthalpy change of solution and is odorless. This compound is widely used for de-icing and dust control.


Preparation of Calcium Chloride

Calcium Chloride can be prepared by the following:

  • By reacting hydrochloric and calcium carbonate solution acid or

  • Directly from the limestone, whereas a large amount is also produced as a by-product of the Solvay process.

The Calcium chloride compound was discovered in the 15th century but received little study or attention until the latter part of the 18th century. All of the entire early work was done with laboratory prepared samples because it was not produced on a commercial scale until after the ammonia-soda process for the manufacture of soda ash was in operation. Actually, it was considered a waste product until the uses were discovered.


Properties of Calcium Chloride (CaCl2)

The important properties of calcium chloride can be tabulated as follows.

CaCl2 compound name

Calcium Chloride

Density

Anhydrous: 2.15 g/cm3

Molecular Weight/ Molar Mass

110.98 g/mol

Boiling Point

1,935 °C

Melting Point

772 °C


CaCl2 Structure

The molecules of Calcium chloride feature two ionic bonds between a single calcium cation and two chloride anions. The calcium chloride structure molecules is represented below. It is to make a note that the calcium cation holds a charge of +2 magnitude, and each chloride anion holds a charge of -1 magnitude. Therefore, the compound is electrically neutral.

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Formula of Calcium Chloride

The chemical formula of calcium chloride can be given as CaCl2.


It is an ionic compound that consists of one calcium cation Ca2+ and two chlorine anions. The bivalent calcium metal forms an ionic bond with two chlorine atoms.


Calcium chloride is an ionic compound, which is made of ions. As we all know that ions either can have positive or negative charges, but the main idea is that the overall ionic compound charge has to balance to get neutral.


Calcium is in the group of 2 with a charge of 2+, and Chlorine is in group 7 with a charge of -1. As the overall charge is 0 for neutral, there must be a balance of charges. Thus, one needs two chlorine ions for balancing the calcium ion charge as 2−2=0.


The formation of cacl2 happens mainly by reacting limestone (CaCo3) with hydrochloric acid (HCl). The chemical equation can be given as follows.


CaCO3 + 2HCl  → CaCl2 + CO2 + H2O(aq)   


It is also produced as a primary by-product while manufacturing the soda ash Na2CO3 using the Solvay process, where the limestone is reacted with NaCl solution.


Preparing Calcium Chloride

To prepare calcium chloride, we need to follow the steps listed below.


Step 1

Take a beaker and place limestones in it by wearing gloves until the beaker is filled up by a quarter of its total volume.


Step 2

Now, add HCl (hydrochloric acid) to 1/4th of a beaker approximately to the limestones.


Step 3

As the hydrochloric acid dissolves limestone, it starts generating bubbles. Now, gently mix the contents in the beaker and be cautious that the reaction completes. If all the limestones dissolve in it completely, add a little limestone.


Step 4

Then, filter off the solids by pouring the solution via filter paper as soon as the solution stops bubbling.


Step 5

Now, heat the second beaker, which has a calcium chloride solution. The solid calcium chloride is that which is left after the water evaporates.


CaCl2 Uses

Calcium chloride has many uses. A few calcium chloride uses are listed below.

  • It is useful as a food preservative, food additive, for de-icing roads in winter, and as brine in refrigeration plants.

  • It is useful as a swimming pool chemical in water treatment plants.

  • It has many applications in oil-well drilling, metallurgy, rubber, dye, paper, and paint industries.

  • It can be used for the correction of mineral deficiencies in brewing beer

  • We can use it in self-heating cans and heating pads.

  • It can also be used as a sterilant for male animals.

Health Hazards of Calcium Chloride

  • Calcium Chloride is an irritating compound and required to be handled with gloves.

  • It is relatively safe to handle, but in case if ingested, it reacts with water exothermically and can cause burning of the esophagus or mouth.

  • It is also recommended for the treatment of acute hypermagnesemia, hyperkalemia, and calcium-channel blocker overdose.

FAQ (Frequently Asked Questions)

1. Is Calcium Chloride Harmful to the Human Body?

Calcium chloride can be used in food production. Also, the Food and Drug Administration (FDA) has classified this substance as GRAS (in general, recognized as safe to eat). It means that the calcium chloride found in foods is edible and is safe for human consumption, only if it is allowed in fewer amounts only.


Also, according to the CDC (Centers for Disease Control and Prevention), it is known to cause skin irritation and the respiratory tract, while prolonged exposure can trigger dermatitis.


A few other possible calcium chlorides dangers that we have to watch out for can be listed as follows.

  • Dizziness

  • Fainting

  • Mood changes

  • Noticing bad taste in your mouth

  • Stomach upset or vomiting

  • Hot flashes

  • Constipation

2. Give Some Disadvantages of Calcium Chloride When Used in Concrete?

Calcium chloride is harmful to concrete, primarily reinforced concrete. It is also responsible for the steel reinforcement corrosion leading to concrete spalling. Nowadays, many concrete structures are either R.C.C or Prestressed or Post-tensioned concrete, whereas steel is used to carry tensile stress.


According to the I.S-12269: 1987, the total chloride content is limited to only 0.05% by mass of cement. The cement manufacturer has to certify this to the consumer within 10 days from the date of manufacturing. The Cement that is used in prestressed and long-span reinforced concrete structures chloride content should not contain more than 0.05%.