Potassium Bromide

KBr: Potassium Bromide

In this content, you will find all important information about potassium bromide uses, its properties and productions. Potassium bromide is a chemical compound of element potassium or K and bromine or Br2. At room temperature, potassium reacts with bromine, and by synthesis, this compound is formed. The chemical equation of this reaction is 🡪 2 K + Br2 = 2KBr. 

Potassium bromide has an immense contribution to medical science. For centuries, this chemical compound has been using as anticonvulsant and sedative. The following discussion is an in-depth discussion about KBr.

What is Potassium Bromide?

Now, the first question that can arise in your mind is “what is potassium bromide”. Thus, here is the answer-

KBr or Potassium bromide is an ionic salt, completely disassociated, and has a value of pH 7 in aqueous solution. It is also known as Kalii bromidum, Tripotassium tribromide, and bromide salt of potassium. This salt can appear as colourless crystals, crystalline powder in white or white grains under standard temperature and pressure. Taste-wise, potassium bromide is pungent bitter with saline flavour. However, this bromide salt tastes sweet in dilute aqueous solutions.

However, if you can increase the concentrations gradually, KBr tastes bitter and eventually becomes salty. This concentration-wise change of taste occurs because of the characteristics of potassium ions. Notably, potassium bromide can irritate the mucous membrane of gastric if consumed in high concentration. Sometimes this may cause vomiting as a general effect of every potassium salt.

This compound is completely water-soluble. This means, when put into water, it can be quickly disassociated into individual ions and disappear. 

Structure of Potassium Bromide

Its structure is created by a single cation K+ and a single anion Br-. The crystalline structure of this salt is precisely octahedral. This structure is formed by one potassium cation surrounded by six bromine anion and also vice versa. For common representation, the chemical structure of potassium bromide can be expressed as below-

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Moreover, to understand the electron representations in the valence shell, you need to learn the Lewis structure. By this electron-dot diagram, you can understand the electron arrangement of individual atoms in a molecule. Also, this diagram can help you to understand how the single pair of electrons can exist inside a molecule. 

This way, it will be easy to understand the reaction between potassium cation and bromine anion, here is the Lewis dot structure of KBr-

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Till now, you learned some common characteristics of this ionic salt. Now, let us move forward to know the other properties of potassium bromide.

  • Physical Properties

For your convenience, here are some physical properties of this salt in a nutshell-

Properties of Potassium Bromide

Properties

Details 

Chemical formula of potassium bromide

KBr

Molar mass of potassium bromide

119.002 gram/mol

Density of KBr

2.74 gram/cm3

Appearance in standard condition

White solid

Structure

Cubic

Occurrence

It does not present in nature

Taste

Bitter, Salty, Pungent, Strong

Odour

Odourless 

Soluble in 

Water, Glycerol, Ethanol

Solubility in water

535 g/L in 0oC, 678 g/L in 25oC, and 1020 g/L in 100oC

Solubility in glycerol

217 g/L

Solubility in ethanol

47.6 g/L in 80oC

Meting point

734oC

Boiling point

1435oC


  • Chemical Properties: Reactions of Potassium Bromide

Typically, potassium bromide is an ionic salt. In aqueous solution, this salt obtains pH balance 7. It notifies that the aqueous solution of KBr is neutral. For manufacturing silver bromide which is a significant component of photographic film, the following reaction is vital.

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

Moreover, bromide in aqueous solution creates complexes while reacting with a few metal halides such as CuBr2 or copper (II) bromide.

2 KBr(aq) + CuBr2(aq) → K2[CuBr4](aq)

Production Process of Potassium Bromide

As said earlier, this potassium salt is not abundant in the environment. However, it has several usages in animal and plant life. Thus, it is important to produce a substantial amount of potassium bromide by chemical reactions.

The most conventional process of manufacturing KBr in industrial scale is through the reaction between potassium carbonate or K2CO3 and iron (III, II) bromide or Fe3Br8. This reaction happen using scrap irons with extra bromine underwater.

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

This is the most economical and effective method to generate potassium bromide.

Quiz

  1. What Kind of Bonding Do You Find In Potassium Bromide?

Options:

  1. Covalent

  2. Metallic

  3. Ionic

  4. None of the above


  1. What Is The Charge of Bromine Ion and Potassium ion, Respectively?

Options:

  1. +1, -1

  2. -1, +1

  3. 0, 0

  4. -2, -1


  1. How Can You Reduce The Halide Anion From a Solution?

Options:

  1. By adding silver ion

  2. By adding bromine ion

  3. By adding potassium ion

  4. None of the above


  1. What Type of Electrolyte Is Potassium Bromide?

Options:

  1. Weak

  2. Not an electrolyte

  3. Strong

  4. None of these options


  1. How Can Bromine Be Separated from Potassium Bromide Solution?

Options:

  1. Chlorine water

  2. Potassium iodide

  3. Iodine solution

  4. Sodium chloride

Answers

  1. Potassium bromide has ionic bonding between its two elements potassium and bromine.

  2. Bromine has -1 charge, and potassium has a +1 charge.

  3. Silver ion can dissolve halide anion out.

  4. Potassium bromide is a strong electrolyte as it can be entirely disassociated in aqueous solution.

  5. As chlorine is considered the stronger oxidising substrate than bromine, it can react with potassium bromide and generate KCl and bromine gas. Here is the chemical equation of this reaction-

2 KBr + Cl2 🡪 2 KCl + Br

Uses of Potassium Bromide

The next important question which arises is “what is potassium bromide used for”. Thus, the following are some crucial usages of KBr.

  • During the 19th or 20th century, this compound was utilised as a medicine against convulsions. However, nowadays, it is majorly used as an antiepileptic medicine for veterinary uses. 

  • One of the most vital usages is as sedatives.

  • Commonly, this is also operated in the infrared spectroscopy technique. This utilisation is majorly performed because of its transparent crystal formation with zero optical absorption.

  • In photographic plates and paper manufacturing industry, it is one of the most widespread chemical compounds.

  • As a heat stabiliser in nylon production, potassium bromide is regarded as a popular chemical agent.

  • It is also used to treat water of aquariums.

  • This is also a popular plasticiser.

  • Some other potassium bromide uses are as laboratory agent and manufacture chemicals.

Application of Potassium Bromide in Veterinary Medicine

Before the introduction of phenobarbital, potassium bromide was licensed to treat several seizure disorders in humans. Nonetheless, it is still regarded as an antiepileptic drug for animals. It works at the cellular level to reduce seizure activities by suppressing neuronal excitability and activity. Potassium bromide can be taken orally and is mostly excreted by the kidneys.

However, it is hardly considered under first-line drugs as it acts slowly and takes nearly four months to achieve a stable concentration of bromide ions inside the brain. Moreover, it is always prescribed along with phenobarbital in initial stages. However, depending on the species of animal, the dose or usages can be different. 

For example, usually, cats are prone to potassium bromide side-effects. Thus, they are mostly treated with this compound. However, dogs can be treated with potassium bromide as per medical practitioner advice. 

Some common side-effects of potassium bromide found in animals are lethargy, vomiting, transient sedation, pancreatitis, polydipsia, anorexia, constipation, and polyuria.

Precautions:

  • The level of bromide ion can be affected by chloride as these two ions compete to take up the cellular membrane. 

  • Low-salt or low-sodium diet can increase the bromide toxicity in animals. Contrarily, a high sodium diet can decrease the bromide level and increase the risk of seizure. 

  • In dogs, the reproductive safety of Br is yet to be proved. However, in humans, Br can go through the placenta and also is present in lactation.

  • Older animals can experience intense adverse side-effects.

Safety Hazards

Besides being used as medicine, it has some significant side-effects as well. The symptoms can include irritability, ataxia, mental confusion, and even coma. In some cases, this chemical compound can cause skin rashes, hallucination, mania, and drowsiness. Potassium bromide in large quantity causes sensory disturbances, vertigo, death, and increases the pressure of the spinal fluid.

Furthermore, potassium salt is a major irritant to eyes. If swallowed in heavy quantity, this substate causes delirium, psychosis, and somnolence.

Hopefully, from the above content, you have understood the chemical compound potassium bromide- KBr, its structure and properties. If you need more reference on potassium bromide uses and applications, you can visit our Vedantu website now. You can also download our Vedantu app for better access.

FAQ (Frequently Asked Questions)

1. What are the potassium bromide uses?

Ans. Potassium bromide, the ionic potassium salt is mostly used as a sedative and anticonvulsant drug to control seizures.

2. What is the working process of potassium bromide?

Ans. Chloride and bromide ions fight to enter brain tissue. If the bromine level becomes greater than chlorine, the electrical activity inside the nervous system is distorted, and the chances of a seizure become difficult.

3. What happens when KBr is dissolved in the water?

Ans. When KBr is dissolved in water, it breaks into K+ or potassium ions and Br- or bromine ions.

4. What kinds of safety hazards are associated with KBr?

Ans. Irritability, mental confusion, ataxia and even coma can be the side-effects of KBr.