Bromine

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Table Of Content

What is Bromine?


Bromine is a chemical element of the Halogen family with atomic number 35. It is represented by symbol Br. It is a diatomic molecule and exists as reddish brown liquid state. Bromine ion (Br-) occurs in sea water in soluble compounds form. An interesting fact about Bromine is that it is only non-metallic element which exists in liquid form.

Bromine in beaker

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Who discovered Bromine?


Bromine was discovered by Antoine Balard in 1826.He accidentally discovered Bromine when he was conducting experiments on sea water.

Antoine Balard

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When sea water was treated with Chlorine yellow orange color Bromine was formed. The following reaction is at the heart of discovery of Bromine.

Reaction of Sea water with Chlorine

The above reaction continues to be at heart of modern day process for extraction of Bromine.

Extraction of Bromine from sea water


When sea water is treated with Chlorine, Bromine is produced. Chlorine which is a stronger oxidizing agent oxidizes Bromine ion (Br-) to Bromine molecule (Br2).

Reaction of Sea water with Chlorine to produce Bromine

The Bromine so produced is removed by steam of air and is passed through Sodium Carbonate solution (Na2CO3). The Bromine gets absorbed on Sodium Carbonate and forms a mixture of Sodium bromide (NaBr) and Sodium bromate (NaBrO3).

Reaction of Br with Sodium Carbonate to produce Sodium bromate

Next step is acidification of solution with Sulphuric acid (H2SO4) and finally distillation is done to get pure Bromine.

Reaction of NaBr, NaBr in acid to produce Br gas

Reaction of NaBr, NaBr in acid to produce Br gas

Uses of Bromine


 

  1. It is used to prepare 1, 2 – Dibromoethane (BrCH2CH2Br) acts as scavenger of lead.
  2. It is used for synthesizing many organic compounds such as MeBr, EtBr etc. MeBr is a nematocide (kills earthworms) and is good insecticide and fungicide.EtBr is a good pesticide used for killing pests.
  3. Silver Bromide (AgBr), a compound of Bromine with silver is light sensitive and is used for photographic film.
  4. Potassium bromide (KBr) is used as a sedative and as an anticonvulsant in treating epilepsy.

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