Test for Calcium Radical

Test for Calcium Radical.. General Aim

Detection of the presence of calcium ion as a base radical in inorganic salts such as calcium chloride.
 

Test for Calcium Ion Method

Detection of the presence of calcium as a base radical using specific chemical reagents.

Test for Calcium Radical: Theoretical Background

Calcium is a metallic element which occupies the 20th element in the periodic table. It is located among group 2 metals that are called alkaline-earth metal. Its chemical symbol is Ca. Calcium is the fifth most abundant element in both Earth’s crust and sea water by mass, where it represents around 3.4% of their mass. Calcium has a silver metallic soft appearance.

Abundance of Calcium in Nature:
Calcium is the fifth most abundant element in Earth’s crust, where it is not commonly found as a pure element. However, it is widely abundant as limestone (CACO3), quick lime (CaO) and calcium fluoride (CaF2).

Properties and Uses of Calcium:
Calcium is the lightest metal on Earth as its density is 1.55 gm/cm3. It was first isolated as pure calcium in the 1800s through electrolysis process. Calcium is an essential element in life. Calcium is one of the main constituents of aquatic organisms’ shells, eggshells, coral reefs, human bones, and cow milk.
 
Calcium Salts:
There are many calcium salts that are used in various purposes. For instance, calcium carbonate is the main constituent of limestone and chalk. Calcite is a fundamental constituent of marbles and pearls. Calcium carbonate is also used as an antacid and as a dietary supplement for treatment of calcium deficiency or osteoporosis. Calcium nitrate is used as a fertilizer.
 
Preparation of Calcium Chloride:
Calcium chloride can be prepared through the reaction of calcium hydroxide and hydrochloric acid as shown below:
 Ca(OH)2 + HCl → CaCl2 + H2O

Properties and Uses of Calcium Chloride:

• Calcium chloride is a white crystalline salt that is highly soluble in water producing colorless aqueous solutions.
• Calcium chloride has the chemical formula of CaCl2 with molecular weight of 110.984 gm/mol.
• Calcium chloride salt possesses a melting point and boiling point of 782 ⁰C and 1600 ⁰C, respectively.
• Calcium chloride is commonly hydrated possessing a general formula of CaCl2.xH2O, where x is the number of water molecules.
• Since calcium chloride is highly hygroscopic in its anhydrous form, it is used as desiccant.  

Test for Calcium Radical.. Principle of Work

In the test for calcium radical experiment, calcium ion in calcium chloride is detected through some identification and confirmatory tests. The calcium radical is among the fifth group of basic radicals.

During the test for calcium radical experiment salt solubility in water will be tested. Then confirmatory tests will be carried out which are ammonium carbonate test, calcium sulfate, potassium chromate and flame test.

First:  Physical Appearance Test:
In this test, the physical appearance of calcium salt is investigated in terms of color, odor, texture, etc.

Second: Solubility Test:
In this test, a sample of the calcium chloride salt is tested for its solubility in cold and hot water if needed.

Third: Ammonium Carbonate Test:
It depends on the fact that ammonium carbonate will react with calcium chloride forming calcium carbonate as white precipitate that crystallizes upon boiling.  

Fourth: Calcium Sulfate Test:
It depends on the fact that no precipitate will be formed as no reaction will be accomplished which confirms that the tested sample is calcium salt.

Fifth: Potassium Chromate Test:
It depends on the fact that no precipitate will be formed as no reaction will be accomplished which confirms that the tested sample is calcium salt.

Sixth: Flame Test:
It is also called a dry test as it uses the calcium chloride salt as it is without dissolving it in water. It depends on the fact that calcium chloride can change the non-luminous benzene flame into an ignited yellowish red colored flame.