Question

Calcium is obtained by:
A) Electrolysis of molten $CaC{{l}_{2}}$
B) Electrolysis of solution of $CaC{{l}_{2}}$ in water
C) Reduction of $CaC{{l}_{2}}$ with carbon
D) Roasting of limestone

Answer 1

It is a factual type of question about the manufacture process related to Calcium.
- For extracting the Ca from its compounds we should use a technique in which there is direct passage of current to the Ca containing solution.

Complete Solution :
- In the question we are asked to state one of the possible ways of extracting elemental Ca from its compounds.
Before directly moving into technique through which Ca is extracted from calcium compounds, let’s discuss some known facts about Ca and brush up our memory.
-We know that Ca is an essential metal in the human body for many life processes and it finds many applications in other industrial sectors also.
-Calcium is the major metal present in bones and teeth of living things and the deficiency of Ca may cause severe diseases like hypocalcaemia and osteoporosis.
-The atomic number of calcium is 20 and has an atomic mass of 40 amu.
-The element Ca belongs to Group-2, i.e. the alkaline earth metal group.
The major and very important ores of Ca are:
-Limestone ($CaC{{O}_{3}}$), Fluorspar$\left( Ca{{F}_{2}} \right)$, Dolomite$\left( CaC{{O}_{3}}.MgC{{O}_{3}} \right)$, Gypsum$\left( CaS{{O}_{4}}.2{{H}_{2}}O \right)$etc.
- And now let’s discuss the manufacturing process of Ca.Ca is extracted from its compound by the techniques of electrolysis.
- Ca is extracted from calcium chloride by carrying out the electrolysis process in its molten form.
- The molten mass consists of six parts of calcium chloride and one part of calcium fluoride and this fused mass undergoes electrolysis at about a temperature of ${{700}^{\circ }}C$ and the graphite acts as the anode cell and a water-cooled cathode of Fe, which is suspended from the top in the fused mass. When the current is passed through the electrolytic set up, the Ca is discharged from the cathode.
$CaC{{l}_{2}}\rightleftharpoons C{{a}^{2+}}+2C{{l}^{-}}$
So, the correct answer is “Option A”.

Note: The $CaC{{l}_{2}}$ is formed as a side product in the Solvay process. $CaC{{l}_{2}}$ is a white crystalline solid at room temperature and it is a good absorbent of moisture and is highly soluble in water.
- The Ca is extracted through an electrolysis process, since this method reduces the unwanted waste production and process is clean.