The key difference between calcium chloride and sodium chloride is that calcium chloride molecule has two chlorine atoms whereas sodium chloride molecule has one chlorine atom. Further, calcium chloride is a white colored powder with hygroscopic properties whereas, sodium chloride is a colorless crystal and the pure sodium chloride is not hygroscopic.
Both calcium chloride and sodium chloride are inorganic, alkaline compounds. The chemical formula of calcium chloride is CaCl2. The chemical formula of sodium chloride is NaCl.
CONTENTS
1. Overview and Key Difference
2. What is Calcium Chloride
3. What is Sodium Chloride
4. Side by Side Comparison – Calcium Chloride vs Sodium Chloride in Tabular Form
5. Summary
What is Calcium Chloride?
Calcium chloride is CaCl2 that has a molar mass of 110.98 g/mol. It appears as a white solid compound which is hygroscopic. This means it can absorb water vapor from the air when exposed to the atmosphere. This compound is odorless. It falls under the category of salts; we call it a salt of calcium.
This compound is highly soluble in water. Due to its hygroscopic nature, this compound commonly occurs as a hydrated complex. The formula of this hydrated complex is CaCl2.(H2O)x in which x = 0, 1, 2, 4 and 6. These hydrated compounds are useful in de-icing processes and controlling dust. The anhydrous form (in which x=0) is important as a descant due to the hygroscopic nature.
Figure 01: Appearance of Calcium Chloride
The melting point of the anhydrous calcium chloride is around 772-775◦C while boiling point is 1935◦C. When we dissolve this compound in water, it forms a hexaaqua complex; [Ca(H2O)6]2+. This converts the calcium and chloride ions in the solution into a “free” state. Therefore, if we add a phosphate source to this aqueous solution, it gives the calcium phosphate solid precipitate.
What is Sodium Chloride?
Sodium chloride is NaCl that has a molar mass of 58.44 g/mol. At room temperature and pressure, this compound appears as solid, colorless crystals. It is odorless. In its pure form, this compound cannot absorb water vapor. Hence, it is not hygroscopic.
Sodium chloride is also a salt; we call it a salt of sodium. There is one chorine atom per each sodium atoms of the molecule. This salt is responsible for the salinity of sea water. The melting point is 801◦C while boiling point is 1413◦C. In sodium chloride crystals, each sodium cation is surrounded with six chloride ions and vice versa. Therefore, we call the crystal system as a face-centered cubic system.
Figure 02: Salt Crystals
This compound dissolves in high polar compounds such as water. There, water molecules surround each cation and anion. Each ion has, most of the times, six water molecules around them. However, the pH of an aqueous sodium chloride lies around pH7 due to the weak basicity of chloride ion. We say, there is no effect of sodium chloride on the pH of a solution.
What is the Difference Between Calcium Chloride and Sodium Chloride?
Calcium chloride is a salt of calcium having the chemical formula CaCl2 whereas sodium chloride is a salt of sodium having the chemical formula NaCl. Both these are salt compounds. Moreover, each calcium chloride molecule has two chlorine atoms per calcium ion while each sodium chloride molecule has one chlorine atom per sodium ion. In addition, their molar masses are different from each other as well; the molar mass of calcium chloride is 110.98 g/mol, and the molar mass of sodium chloride is 58.44 g/mol.
Summary – Calcium Chloride vs Sodium Chloride
Calcium chloride and sodium chloride are salt compounds which are alkaline. Both these compounds contain chloride ions in their structure, but in different ratios. The key difference between calcium chloride and sodium chloride is that one calcium chloride molecule has two chlorine atoms whereas one sodium chloride molecule has one chlorine atom.
Reference:
1. “Calcium Dichloride.” National Center for Biotechnology Information. PubChem Compound Database. U.S. National Library of Medicine. Available here
2. “Sodium Chloride.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine. Available here
Image Courtesy:
1.’Calcium chloride CaCl2’By No machine-readable author provided. (CC BY-SA 3.0) via Commons Wikimedia
2.’Halit-Kristalle’By W.J.Pilsak at German Wikipedia (CC BY-SA 3.0) via Commons Wikimedia