How Potassium Bromide Is Produced and Used in Chemistry
In this content, you will find all important information about potassium bromide uses, its properties, and production. Potassium bromide is a chemical compound of the 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 used 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 an aqueous solution. It is also known as Kalii bromidum, Tripotassium tribromide, and bromide salt of potassium. This salt can appear as colorless crystals, crystalline powder in white or white grains under standard temperature and pressure. Taste-wise, potassium bromide is pungent bitter with saline flavor. 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 the gastric if consumed in high concentrations. 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 anions 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 a 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
Chemical Properties
Potassium Bromide Reactions: It is a typical ionic salt that is completely dissociated in an aqueous solution at a pH of around 7. In the production of silver bromide for photographic films, this reaction is crucial. The following is the reaction:
KBr(aq) + AgNO3(aq) → AgBr(s) + KNO3(aq)
When bromide reacts with metal halides like copper (II) bromide in its aqueous state, it forms complexes:
2 KBr(aq) + CuBr2(aq) → K2[CuBr4](aq)
Quiz
What Kind of Bonding Do You Find In Potassium Bromide?
Options:
Covalent
Metallic
Ionic
None of the above
What Is The Charge of Bromine Ion and Potassium ion, Respectively?
Options:
+1, -1
-1, +1
0, 0
-2, -1
How Can You Reduce The Halide Anion From a Solution?
Options:
By adding silver ion
By adding bromine ion
By adding potassium ion
None of the above
What Type of Electrolyte Is Potassium Bromide?
Options:
Weak
Not an electrolyte
Strong
None of these options
How Can Bromine Be Separated from Potassium Bromide Solution?
Options:
Chlorine water
Potassium iodide
Iodine solution
Sodium chloride
Answers
Potassium bromide has ionic bonding between its two elements potassium and bromine.
Bromine has a -1 charge, and potassium has a +1 charge.
Silver ions can dissolve halide anions out.
Potassium bromide is a strong electrolyte as it can be entirely dissociated in an aqueous solution.
As chlorine is considered the stronger oxidizing 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 + Br2
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 utilized 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 utilization is majorly performed because of its transparent crystal formation with zero optical absorption.
In the photographic plates and paper manufacturing industry, it is one of the most widespread chemical compounds.
As a heat stabilizer in nylon production, potassium bromide is regarded as a popular chemical agent.
It is also used to treat aquariums.
This is also a popular plasticiser.
Some other potassium bromide used are as laboratory agents 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, 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 diets can increase bromide toxicity in animals. Contrarily, a high sodium diet can decrease the bromine 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.
How are Bromides Given
Bromides are taken by mouth as a chewable pill or liquid solution, and should be taken with meals to reduce stomach distress. It can either be incorporated with food or given straight by mouth with a meal as long as the complete dose is consumed. Elevate the food dish if it has been blended into the food. To avoid discomfort in the mouth or throat, ensure the capsule is thoroughly taken and followed by food or drink. With a precise measuring device/syringe, carefully measure liquid dosages. If gastrointestinal distress persists after taking the medication with food, divide the one daily dose into several doses spread out over a 24-hour period. Salty meals should not be given. If your veterinarian advises, do not abruptly cease using this medicine. It may take a few weeks for the full effects of this drug to become apparent, although incremental improvements are normally seen. Side effects might happen right away.
Potassium Bromide Drug Information and Indication
Potassium bromide is an antiepileptic medication used in dogs to treat seizures that cannot be controlled by phenobarbital alone or in dogs that do not handle phenobarbital well. Potassium bromide reduces seizure activity in the central nervous system. Because of the high prevalence of adverse effects, cats are less likely to be treated with potassium bromide. Although potassium bromide is an efficient medication, it might take up to four months for the concentration to reach effective levels. Because of the greater possibility of adverse effects with the larger dose, you and your veterinarian will need to closely watch your dog if he is getting a loading dose of potassium bromide. The level of the antiepileptic medicine in your dog's blood will need to be measured on a frequent basis. Your veterinarian will create a suitable dosage for your dog based on this information. Your dog will very certainly be treated for the rest of their life.
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 quantities causes sensory disturbances, vertigo, death, and increases the pressure of the spinal fluid.
Furthermore, the potassium salt is a major irritant to the 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 its properties. If you need more references on potassium bromide uses and applications, you can visit our Vedantu website now. You can also download our Vedantu app for better access.
FAQs on Potassium Bromide: Structure, Properties, and Applications
1. What is potassium bromide (KBr) and what are its fundamental characteristics?
Potassium bromide, with the chemical formula KBr, is an ionic salt composed of potassium cations (K⁺) and bromide anions (Br⁻). Under standard conditions, it exists as a white, crystalline powder. It is well-known for being an alkali metal halide and serves various roles in chemistry and medicine.
2. What are the key physical and chemical properties of potassium bromide?
Potassium bromide exhibits several distinct properties that are important for students to know:
- Appearance: It is a white crystalline solid at room temperature.
- Solubility: KBr is freely soluble in water but poorly soluble in non-polar or less polar organic solvents like acetonitrile.
- Taste: Its taste varies with concentration. In dilute aqueous solutions, it tastes sweet, becomes bitter at higher concentrations, and tastes salty at very high concentrations.
- Structure: It forms a crystal lattice with a rock salt structure, similar to sodium chloride (NaCl).
- Chemical Nature: It is a typical ionic salt that completely dissociates in water.
3. How is the crystal structure of potassium bromide (KBr) described in solid-state chemistry?
The crystal structure of potassium bromide is a classic example of the rock salt (halite) structure. It crystallises in a cubic system with a face-centred cubic (FCC) lattice. In this arrangement, each potassium ion (K⁺) is surrounded by six bromide ions (Br⁻), and each bromide ion is similarly surrounded by six potassium ions. This results in a coordination number of 6:6 for the crystal.
4. What are the main applications and uses of potassium bromide?
Potassium bromide has several important applications, including:
- Veterinary Medicine: It is widely used as an anticonvulsant drug to treat epilepsy in dogs, often in conjunction with phenobarbital.
- Infrared (IR) Spectroscopy: Due to its transparency to infrared radiation over a wide wavelength range, KBr is used to make optical windows and pellets for holding solid samples during IR analysis.
- Photography: Historically, it was used in the preparation of silver bromide (AgBr), a light-sensitive chemical essential for photographic films and papers.
- Sedative: In the past, it was used in human medicine as a sedative and hypnotic, though this use has largely been discontinued due to its side effects.
5. What happens at the ionic level when potassium bromide is dissolved in water?
When potassium bromide (KBr), an ionic solid, is dissolved in water (a polar solvent), the process of dissociation occurs. The polar water molecules surround the individual ions in the crystal lattice, overcoming the electrostatic forces holding them together. The compound breaks apart into free-moving, hydrated ions: potassium cations (K⁺(aq)) and bromide anions (Br⁻(aq)). This is why a KBr solution is a good conductor of electricity.
6. How does potassium bromide work as an anticonvulsant from a chemical standpoint?
The anticonvulsant effect of potassium bromide is based on the interaction of bromide ions with nerve cells. Bromide ions (Br⁻) compete with chloride ions (Cl⁻) to pass through ion channels in the neuronal membrane, particularly GABA-activated channels. Since bromide ions are more permeable, their entry causes a greater influx of negative charge, leading to hyperpolarization of the neuron. This raises the seizure threshold, making it more difficult for nerve cells to fire rapidly and uncontrollably, thus suppressing seizure activity.
7. Why is potassium bromide highly soluble in water but not in many organic solvents?
This difference in solubility is explained by the chemical principle "like dissolves like." Potassium bromide is a highly polar ionic compound. Water is also a highly polar solvent. The partial positive and negative charges on water molecules can effectively surround and stabilise the K⁺ and Br⁻ ions, a process called hydration, which overcomes the crystal lattice energy. In contrast, most organic solvents are non-polar or less polar and cannot effectively solvate these ions, resulting in poor solubility.
8. What kind of safety precautions should be taken when handling potassium bromide in a lab?
While not highly toxic in small amounts, potassium bromide requires careful handling. Prolonged exposure or ingestion can lead to a condition called bromism, with symptoms including mental confusion, irritability, and skin rashes. In a laboratory setting, one should always wear appropriate personal protective equipment (PPE), such as gloves and safety glasses, and handle it in a well-ventilated area to avoid inhaling the dust.
