What is the Difference Between Bromine and Bromine Water

The main difference between bromine and bromine water is that bromine is a diatomic molecule composed of two bromine atoms, whereas bromine water is a solution of bromine gas in water.

Bromine and bromine water are interconnected elements in chemistry. Both bromine and bromine water find use in laboratory tests, with bromine water commonly used in chemical analyses, such as the bromine water test for detecting unsaturation in organic compounds.

Key Areas Covered

1. What is Bromine  
      – Definition, Features, Uses
2. What is Bromine Water
      – Definition, Features, Uses
3. Similarities Between Bromine and Bromine Water
      – Outline of Common Features
4. Difference Between Bromine and Bromine Water
      – Comparison of Key Differences
5. FAQ: Bromine and Bromine Water
      – Frequently Asked Questions

Key Terms

Bromine, Bromine Water

Difference Between Bromine and Bromine Water - Comparison Summary

What is Bromine

Bromine is a diatomic molecule with the chemical formula Br2. In its pure elemental form, bromine is a dark red-brown liquid at room temperature. This liquid state is a result of its relatively low boiling point of 58.8 degrees Celsius (137.8 degrees Fahrenheit), which is higher than that of chlorine and lower than that of iodine, the other halogens.  Furthermore, it possesses a strong and unpleasant odor, which is characteristic of halogens. Its color and odor make bromine easily recognizable and distinguishable in laboratory and industrial settings.

Bromine is relatively dense, and its density is around 3.14 grams per cubic centimeter. It is also sparingly soluble in water. Its solubility increases with the presence of certain solvents, such as organic solvents like carbon tetrachloride. Bromine is highly reactive due to its position in the halogen group. It readily forms compounds with other elements and exhibits a tendency to replace less reactive halogens in certain chemical reactions. The reactivity of bromine is harnessed in various chemical processes and applications.

Compare Bromine and Bromine Water

One of the significant applications of bromine is in the production of flame retardants. Bromine compounds, such as brominated flame retardants, are incorporated into materials like plastics, textiles, and electronics to reduce their flammability. These flame retardants work by interfering with the combustion process, making materials more fire-resistant. Bromine is employed in the synthesis of various chemicals. Its ability to participate in substitution and addition reactions makes it valuable in organic chemistry. For example, bromine is used in the synthesis of pharmaceuticals, agrochemicals, and certain specialty chemicals.

What is Bromine Water

Bromine water is characterized by its reddish-brown color, which is a result of the presence of dissolved bromine gas. This distinctive color makes it easy to identify and differentiate from other solutions. Similar to pure bromine, bromine water exhibits a strong and somewhat unpleasant odor. This odor is characteristic of halogens, a group of elements to which bromine belongs. The chemical composition of bromine water involves the dissolution of bromine gas in water. The resulting solution contains bromine molecules and hydrated bromine ions. Bromine water is sparingly soluble in water. While it dissolves to a certain extent, it may not fully dissociate due to the relatively low solubility of bromine in water. The addition of organic solvents, such as carbon tetrachloride, can enhance the solubility of bromine in water.

Bromine vs Bromine Water

Bromine water is widely used in organic chemistry for unsaturation tests. Unsaturated organic compounds, such as alkenes and alkynes, readily react with bromine. The bromine molecules add across the carbon-carbon double or triple bonds, resulting in a decolorization of the bromine water. This reaction is a quick and visual method for identifying the presence of unsaturation in a compound. The decolorization of bromine water is a characteristic reaction of alkenes and alkynes. Alkenes undergo addition reactions with bromine, breaking the pi bond and forming a bromonium ion intermediate. Alkynes, which have a triple bond, undergo similar addition reactions, leading to the decolorization of bromine water. Bromine water can participate in redox reactions, serving as an oxidizing agent. Moreover, in certain chemical reactions, bromine water can oxidize substances, and its color changes due to the reduction of bromine to bromide ions. This property makes it useful in studying redox chemistry.

Similarities Between Bromine and Bromine Water

  • Both bromine and bromine water exhibit a reddish-brown color.
  • Both bromine and bromine water find use in laboratory tests.

Difference Between Bromine and Bromine Water


Bromine refers to the elemental form of the halogen bromine, represented by the diatomic molecule Br2, whereas bromine water is a solution of bromine gas (Br2) in water (H2O).


Bromine is sparingly soluble in water. It can dissolve to some extent, but its solubility is limited. Meanwhile, bromine water is a solution where bromine gas dissolves in water.

FAQ: Bromine and Bromine Water

What is the common name for bromine water?

Bromine solution is a common name for bromine water.

What are the two types of bromine?

Br 79 and Br 81 are two types of bromine.

What is bromine water used for?

Bromine water is commonly used to test the presence of alkenes.


Bromine, represented by the symbol Br and atomic number 35, is a halogen that exists as a reddish-brown liquid at room temperature, known for its reactivity and applications in various chemical processes. Bromine water, on the other hand, is a solution of bromine dissolved in water, sharing the distinctive reddish-brown color of its elemental form. Thus, this is the main difference between bromine and bromine water.


1. “Bromine.” Encyclopedia Britannica. 
2. “Bromine Water.” Wikipedia. Wikipedia Foundation.

Image Courtesy:

1. “Bromine vial in acrylic cube” By Alchemist-hp (pse-mendelejew.de) – Own work (CC BY-SA 3.0 de) via Commons Wikimedia
2. “Bromine water” By Matthew Sergei Perrin from Auckland, New Zealand – Bromine Water (CC BY 2.0) via Commons Wikimedia

About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.

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