Potassium Bromide (KBr) is a chemical compound made of potassium and bromine. It is commonly used in photography, medicine, and veterinary medicine as an anticonvulsant for dogs.
| IUPAC Name | Potassium Bromide |
| Molecular Formula | KBr |
| CAS Number | 7758-02-3 |
| Synonyms | Bromide of potassium, Bromide salt of potassium, Kaliobromid, Bromopotassium |
| InChI | InChI=1S/BrH.K/h1H;/q;+1/p-1 |
Potassium Bromide Properties
Potassium Bromide Formula
The chemical formula for Potassium Bromide is KBr. This formula represents the ratio of atoms in the compound. The K+ ion has a charge of +1, and the Br- ion has a charge of -1, resulting in a neutral compound. The formula is used to indicate the composition of the compound and is essential in writing balanced chemical equations.
Potassium Bromide Molar Mass
KBr has a molar mass of 119.01 g/mol. It is made up of one potassium atom and one bromine atom. The molar mass is an important characteristic of a compound as it is used to determine the number of moles of a substance in a given sample. It is also used in stoichiometry to calculate the mass of a product or reactant in a chemical reaction.
Potassium Bromide Boiling Point
KBr has a boiling point of 1,390°C (2,534°F). This high boiling point is due to the ionic nature of the compound. When heated, the ionic bonds between potassium and bromine require a large amount of energy to break, resulting in a high boiling point. KBr is commonly used in the laboratory as a heat transfer medium due to its high boiling point.
Potassium Bromide Melting Point
KBr has a melting point of 734°C (1,353°F). Like the boiling point, the melting point is also determined by the strength of the ionic bonds between the potassium and bromine atoms. When heated, the ionic bonds are weakened, and the crystal lattice structure of the compound breaks down, resulting in a liquid state.
Potassium Bromide Density g/mL
The density of KBr is 2.75 g/mL at room temperature. The density of a substance is defined as the mass of a substance per unit volume. The high density of KBr is due to the closely packed crystal structure of the compound. This property makes it useful in the manufacturing of optical materials such as lenses and prisms.
Potassium Bromide Molecular Weight
The molecular weight of KBr is 119.01 g/mol. This value is calculated by adding the atomic masses of potassium and bromine. Molecular weight is used in chemical calculations such as determining the amount of a substance required to make a solution of a specific concentration.
Potassium Bromide Structure
KBr has a crystal structure consisting of a face-centered cubic lattice. Each K+ ion is surrounded by six Br- ions, and each Br- ion is surrounded by six K+ ions. This arrangement is characteristic of ionic compounds, which have a regular, repeating arrangement of ions in the crystal structure.
| Appearance | White crystalline solid |
| Specific Gravity | 2.75 g/mL at 25°C |
| Color | Colorless |
| Odor | Odorless |
| Molar Mass | 119.01 g/mol |
| Density | 2.75 g/cm³ |
| Melting Point | 734°C (1,353°F) |
| Boiling Point | 1,390°C (2,534°F) |
| Flash Point | Not applicable |
| Water Solubility | 53 g/100 mL at 20°C |
| Solubility | Soluble in alcohol, acetone, and ammonia |
| Vapour Pressure | 1 mmHg at 1,114°C |
| Vapour Density | Not applicable |
| pKa | 7.5 (at 25°C) |
| pH | 7 (Neutral) |
Potassium Bromide Safety and Hazards
KBr is generally considered to be safe for use, but it can pose certain hazards if handled improperly. It is a skin, eye, and respiratory irritant, and ingestion can cause gastrointestinal distress. Prolonged exposure to high concentrations can cause respiratory problems. KBr should be handled with care and proper personal protective equipment, including gloves and a dust mask, should be worn when handling the compound. It is also important to store KBr in a cool, dry, and well-ventilated area away from incompatible materials. In case of exposure, seek medical attention immediately.
| Hazard Symbols | Xi – Irritant |
| Safety Desc | Avoid contact with skin and eyes. Wear suitable protective clothing, gloves and eye/face |
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| UN IDs | UN 1465 (Chemicals, Potassium Bromide) |
| HS Code | 28275100 |
| Hazard Class | 6.1 (Toxic substances) |
| Packing Group | III |
| Toxicity | LD50 (oral, rat) = 2,340 mg/kg |
Potassium Bromide Synthesis Methods
To synthesize KBr, one can use various methods such as direct synthesis, double decomposition, and acid-base titration.
KOH reacts with HBr gas to produce KBr in direct synthesis. The reaction produces KBr and water as byproducts.
Double decomposition involves the reaction of a soluble Potassium salt with a soluble Bromide salt, such as Potassium chloride and Sodium Bromide. The reaction produces KBr and Sodium Chloride.
Acid-base titration involves the reaction of a Bromide salt with KOH. The dilute sulfuric acid first treats the Bromide salt to form Hbr, and then KOH titrates it to produce KBr and water.
Another method of synthesizing KBr involves the reaction of Bromine with a hot Potassium hydroxide solution. Sodium sulfite reduces Potassium Bromate, producing KBr and Potassium Bromate.
Potassium Bromide Uses
KBr has several uses in various industries due to its unique properties. Here are some of the common uses of KBr:
- Photography: Widely used in black and white photography as a photographic fixative to prevent the photographic paper from fogging.
- Veterinary medicine: Used as an anticonvulsant medication for dogs and cats suffering from seizures.
- Analytical chemistry: Used as a reference standard in Fourier transform infrared (FTIR) spectroscopy to identify organic compounds.
- Medicinal chemistry: Used in the preparation of various pharmaceuticals, including sedatives, hypnotics, and antiepileptics.
- Oil drilling: Used as a completion fluid in oil drilling to prevent the influx of formation water and reduce the risk of corrosion.
- Flame retardants: Used as a flame retardant in plastics, textiles, and paper products.
- Chemical synthesis: Also used in chemical synthesis reactions, particularly in the synthesis of various organic and inorganic compounds.
Questions:
Q: Under what conditions can potassium bromide conduct electricity?
A: KBr can conduct electricity when it is in a molten state or when it is dissolved in water, which allows its ions to move freely and carry an electrical charge.
Q: Is KBr ionic or covalent?
A: KBr is an ionic compound, formed by the transfer of electrons from Potassium to Bromine.
Q: Is KBr soluble in water?
A: Yes, KBr is highly soluble in water, with a solubility of 53.5 g/100 mL at 25°C.
Q: What is the formula for potassium bromide?
A: The chemical formula for Potassium Bromide is KBr.
Q: Is KBr an acid or base?
A: KBr is a salt and does not have acidic or basic properties.
Q: What is KBr?
A: KBr is the chemical symbol for Potassium Bromide, an ionic compound used in various industries for its unique properties.
Q: What mass of KBr (in grams) do you need to make 250.0 mL of a 1.50 M KBr solution?
A: To make a 1.50 M KBr solution in 250.0 mL of water, you would need to dissolve 30.4 grams of KBr in the water.