Difference Between Chloroform and Chlorine

Main Difference – Chloroform vs Chlorine

Chlorine is a chemical element having the atomic number 17. But in general, the term chlorine is used to call chlorine gas, the diatomic gaseous compound of chlorine. Chlorine gas and other chlorine-containing compounds are very useful as a disinfectant and for the manufacture of other products. Chloroform is a common anesthetic compound formed by the reaction between methane and chlorine gas. The main difference between chloroform and chlorine is that chloroform exists as a liquid at room temperature and has a heavy, ether-like odor and a sweet taste whereas chlorine exists as a yellowy-green gas and has a chocking smell.

Key Areas Covered

1. What is Chloroform
      – Definition, Chemical Properties, Production, Uses
2. What is Chlorine
     – Definition, Chemical Properties, Uses
3. What is the Difference Between Chloroform and Chlorine
     – Comparison of Key Differences

Key Terms: Atomic Number, Chloride, Chlorine, Chloroform, Free Radical Halogenation, Isotope, Methane, Tetrahedral, Trichloromethane

What is Chloroform

Chloroform is a common anesthetic (a substance that induces insensitivity to pain) chemical species having the chemical formula CHCl₃. The molar mass of this compound is 119.369 g/mol. It is also called trichloromethane because the chemical structure of chloroform resembles methane with three hydrogen atoms substituted by chlorine atoms.

Figure 1: Chemical Structure of Chloroform

At room temperature, chloroform exists as a colorless liquid that is highly volatile. It has a heavy, ether-like odor and a sweet taste. The melting point of chloroform is −63.5 °C and the boiling point is 61.15 °C. But it decomposes at 450 °C. Chloroform is slightly soluble in water but is well-soluble in organic solvents such as benzene. Chloroform is denser than water (1.489 g/cm³ at 25^oC). The geometry of the chloroform molecule is tetrahedral.

Figure 2: Chloroform

Chloroform is produced via chlorination of methane. Here, a mixture of chlorine and methane is heated to about 400^oC. Chlorination occurs as a free radical halogenation.

CH₄        +    Cl₂   →   CH₃Cl   +   HCl

CH₃Cl     +    Cl₂   →   CH₂Cl₂  +   HCl

CH₂Cl₂   +    Cl₂   →   CHCl₃   +   HCl

The most important use of chloroform is the production of monochlorodifluoromethane (CFC-22) via the reaction between chloroform and HF (hydrogen fluoride). It is also used as a solvent for fats, oils, rubber, etc. When the hydrogen atoms of chloroform are replaced with deuterium isotope, it gives CDCl₃, which is the solvent used in NMR spectroscopy. However, most common use of chloroform is its use as an anesthetic. It was widely used in surgeries and in criminal activities as well. However, use of chloroform in surgeries is now strictly controlled as they can cause liver damage.

What is Chlorine

Chlorine is a chemical element having the atomic number 17. Chlorine is in the group 17 of the periodic table, which is called halogen group and belongs to the p block. It is a nonmetal. The electron configuration of chlorine is [Ne]3s²3p⁵. It lacks one electron to fill the orbitals completely. Hence, chlorine atoms are very reactive; chlorine forms anions with -1 electrical charge by gaining one electron from the outside in order to complete the electron configuration. But in general, the name chlorine is used to name the chlorine diatomic gas (Cl₂).

Figure 3: Chlorine Gas in a Sphere

At room temperature and pressure, chlorine exists as a yellowy-green gas. Chlorine gas has a chocking smell. There are few isotopes of chlorine. The most common isotopes are Chlorine-35 and chlorine-37. However, chlorine-35 is the most abundant isotope among these two due to its high stability. The most stable oxidation state of chlorine is -1. By obtaining one electron from outside (from an electron donating chemical species), chlorine atom can get a stable electron configuration by completing the electron configuration.

Chlorine gas and most other chlorine-containing compounds can kill bacteria. Hence, it is used as a disinfectant to treat drinking water and swimming pool water. However, chlorine gas is mainly used in the production of PVC (polyvinyl chloride).

Chlorine gas can be used as an oxidizing agent because Cl₂ can be reduced to form chloride ions (Cl^– anions are known as chloride ions). Another major application of chlorine is in ion manufacture of chloroform, which is an anesthetic.

Difference Between Chloroform and Chlorine

Definition

Chloroform: Chloroform is a common anesthetic chemical species having the chemical formula CHCl₃.

Chlorine: Chlorine is a chemical element having the atomic number 17 and the symbol Cl. But in general, diatomic chlorine is also called as chlorine.

Molar Mass

Chloroform: The molar mass of Chloroform is 119.369 g/mol.

Chlorine: The atomic weight of chlorine atom is 35.453 amu.

Nature

Chloroform: Chloroform is a volatile liquid at room temperature.

Chlorine: Chlorine is a diatomic gas at room temperature.

Physical Properties

Chloroform: Chloroform has a heavy, ether-like odor and a sweet taste.

Chlorine: At room temperature and pressure, chlorine exists as a yellowy-green gas and has a chocking smell.

Uses

Chloroform: Chloroform is used for the production of monochlorodifluoromethane and is used as a solvent for fats, oils, rubber, etc. It was used as an anesthetic chemical, but now the usage is controlled.

Chlorine: Chlorine-containing compounds are mainly used as disinfectants and chlorine is used for the production of chemical compounds such as PVC.

Conclusion

Chloroform is produced from the free radical halogenation reaction between methane and chlorine. Chloroform was commonly used as an anesthetic chemical, but now the usage is controlled due to its damage to the liver. Chlorine is a chemical element having the atomic number 17. At room temperature, it exists as diatomic chlorine gas. The main difference between chloroform and chlorine is that chloroform exists as a liquid at room temperature and has a heavy, ether-like odor whereas chlorine exists as a yellowy-green gas and has a chocking smell.

Reference:

1. “Chlorine – Element information, properties and uses | Periodic Table.” Royal Society of Chemistry, Available here.
2. “CHLOROFORM.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
3. Carey, Francis A. “Chloroform.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 15 Nov. 2017, Available here.

Image Courtesy:

1. “Chloroform displayed” By Original image by Benjah-bmm27, vectorized by Fvasconcellos – Image:Chloroform-2D.png (Public Domain) via Commons Wikimedia
2. “Chloroform by Danny S. – 002” By Danny S. – Own work (CC BY-SA 3.0) via Commons Wikimedia
3. “Chlorine sphere” By W. Oelen – (CC BY-SA 3.0) via Commons Wikimedia