The key difference between chlorine and sodium hypochlorite is that the chlorine (Cl2) is a pale yellow color gas whereas the sodium hypochlorite (NaOCl) is a greenish-yellow solid at room temperature.
Chlorine and sodium hypochlorite are chemical compounds of the chemical element chlorine (Cl). The term chlorine chemically describes the chemical element, but in common it is the name for chlorine gas, which we use for cleaning purposes. Sodium hypochlorite, on the other hand, is a common liquid bleach.
CONTENTS
1. Overview and Key Difference
2. What is Chlorine
3. What is Sodium Hypochlorite
4. Side by Side Comparison – Chlorine vs Sodium Hypochlorite in Tabular Form
5. Summary
What is Chlorine?
Chlorine is a gas at room temperature having the chemical formula Cl2. It has a pale yellow color appearance, and it is an extremely reactive agent. Therefore, it can act as a strong oxidizing agent. Apart from that, this gas has a pungent and irritating odor similar to bleach that we normally use. In the IUPAC nomenclature, we name this compound as molecular chlorine.
The molar mass of this compound is 70.9 g/mol. The chlorine gas molecule contains two chlorine atoms bonded to each other via a covalent chemical bond. Therefore we name it as a diatomic molecule. Moreover, this gas is slightly soluble in water. We can also liquefy this gas at about -35◦C. Or else we can liquefy it by applying an external pressure to compress the gas at room temperature. The chlorine gas is inflammable, but it can aid combustion.
Figure 01: Liquefied Chlorine Gas
The inhalation of chlorine gas is toxic. It also acts as an irritant to the eye. In addition to that, this gas is heavier than the normal air. Therefore, it easily collects in the lower atmosphere. Since it exists as a gas at room temperature, the melting and boiling points are -101°C and -35°C respectively. When considering the uses of this gas, there are three major uses; sanitation, disinfection and antiseptic applications. Moreover, some people use it as a chemical weapon as well.
What is Sodium Hypochlorite?
Sodium hypochlorite is an inorganic compound having the chemical formula NaOCl. It is a greenish-yellow solid at room temperature. The molecule contains a sodium cation and a hypochlorite anion. These two ions link with each other via electrostatic interactions. Moreover, we can classify this compound as a sodium salt of hypochlorous acid, considering the parent molecule of the compound; the parent molecule is hypochlorous acid.
Figure 02: Sodium Hypochlorite Molecule
The molar mass is 74.44 g/mol. It has chlorine-like odor. Yet it has a sweet odor. Since it exists as a solid at room temperature, the melting and boiling points are positive values; melting and boiling points are 18 °C and 101 °C respectively.
Often we name a greenish-yellow solution as the sodium hypochlorite because this solution made from the dissolution of the solid in water gives the common liquid bleach that we use in the household. Moreover, the solid compound is unstable. Thus it can decompose explosively. We can crystallize this compound as its pentahydrate. This hydrated compound is very stable; thus, we can store it in a refrigerator. In its liquid bleach form, the chemical compound in the solution liberate chlorine gas. However, this chemical compound is not that much toxic or corrosive like chlorine gas. The major uses of this compound include bleaching, cleaning, disinfection, deodorizing, wastewater treatments, etc.
What is the Difference Between Chlorine and Sodium Hypochlorite?
Chlorine is a gas at room temperature which has the chemical formula Cl2 whereas sodium hypochlorite is an inorganic compound having the chemical formula NaOCl. This is the fundamental difference between chlorine and sodium hypochlorite. Both these are important as bleaching agents, disinfectants, etc. When considering the chemical bonding, the difference between chlorine and sodium hypochlorite is that the chlorine has a covalent chemical bond between two chlorine atoms while the sodium hypochlorite has an electrostatic attraction force between sodium cation and hypochlorite anion. We can consider their appearances as the key difference between chlorine and sodium hypochlorite. Chlorine is a pale yellow colored gas whereas sodium hypochlorite is a greenish-yellow solid at room temperature. Moreover, chlorine gas is highly toxic when compared to the toxicity of sodium hypochlorite.
The below infographic provides more information on the difference between chlorine and sodium hypochlorite.
Summary – Chlorine vs Sodium Hypochlorite
Both chlorine gas and sodium hypochlorite are important as bleaching agents and disinfectants. Chlorine gas itself is oxidative while sodium hypochlorite can liberate chlorine gas for its applications. The key difference between chlorine and sodium hypochlorite is that chlorine is a pale yellow colored gas whereas sodium hypochlorite is a greenish-yellow solid at room temperature.
Reference:
1. “Sodium Hypochlorite.” Wikipedia, Wikimedia Foundation, 9 Sept. 2018. Available here
2. “Chlorine.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine. Available here
Image Courtesy:
1.”Liquid Pool Chlorine”By Maksym Kozlenko – Own work, (CC BY-SA 4.0) via Commons Wikimedia
2.”Sodium-hypochlorite”By Benjah-bmm27 – Own work, (Public Domain) via Commons Wikimedia