Potassium Bromide - KBr

What is Potassium Bromide?

KBr is a salt which is widely used as a sedative and as an anticonvulsant with chemical name Potassium Bromide. It is also called Bromide salt of potassium or Kalii bromidum or Tripotassium tribromide.

Bromide salt of potassium is odourless, and is obtained as white crystalline powder or colorless crystals or white granular solid which has a pungent bitter saline taste. Aqueous solutions have a pH value of 7.

Properties of Potassium Bromide – KBr


Potassium Bromide

Molecular weight of KBr

119.002 g/mol

Density of Potassium Bromide

2.74 g/cm3

Melting point of Potassium Bromide

734 °C

Boiling point of Potassium Bromide

1,435 °C

Potassium Bromide structure – KBr

Potassium Bromide structure

KBr Uses (Potassium Bromide)

  • Potassium Bromide is used to manufacture photographic papers and plates.
  • Used as a laboratory agent.
  • Used as heat stabilizer for nylon.
  • Used as a Sedative.
  • Used as an anticonvulsant.
  • Used in the water treatment of aquariums
  • Used to manufacture chemicals.
  • Used as plasticizers.

Production of Potassium Bromide

One of the traditional methods of producing KBr is by reacting potassium carbonate with an iron (III, II) bromide. The reaction is as follows.

4 K2CO3 + Fe3Br8 → 8 KBr + Fe3O4 + 4 CO2

Potassium Bromide Reactions

It is a typical ionic salt which is fully dissociated at near pH value of 7 in the aqueous solution. This reaction plays an important role in the manufacture of silver bromide for photographic films. The reaction is as follows:

KBr(aq) + AgNO3(aq) → AgBr(s) + KNO3(aq)

Bromide in its aqueous form, produces complexes on reacting with metal halides like copper (II) bromide:

2 KBr(aq) + CuBr2(aq) → K2[CuBr4](aq)

Health hazards

Some of the symptoms include vomiting, ataxia, coma, irritability, and mental confusion. It can cause mania, skin rashes, drowsiness, and hallucinations. It also causes neurological signs, increased spinal fluid pressures, death, vertigo, and sensory disturbances.

Learn more about the Structure, physical and chemical properties of KBr from the experts at BYJU’S.

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