Sodium bromide (NaBr) is a salt that is used in photography, oil and gas drilling, and as a sedative. It dissolves easily in water and has a white crystalline appearance.
| IUPAC Name | Sodium bromide |
| Molecular Formula | NaBr |
| CAS Number | 7647-15-6 |
| Synonyms | Bromide of soda, Bromnatrium, Sodium bromatum, UNII-84S7BG5R0T |
| InChI | InChI=1S/BrH.Na/h1H;/q;+1/p-1 |
Sodium Bromide Properties
Sodium Bromide Formula
The chemical formula of sodium bromide is NaBr. It indicates that one sodium atom is bonded to one bromine atom through an ionic bond. The formula of a compound represents the ratio of atoms in the molecule and is essential in chemical reactions and stoichiometry calculations.
Sodium Bromide Molar Mass
The molar mass of NaBr is 102.89 g/mol. This is calculated by adding the atomic masses of one sodium atom and one bromine atom together. The molar mass of a compound is important for various calculations in chemistry, such as determining the number of moles of a substance in a given sample.
Sodium Bromide Boiling Point
The boiling point of NaBr is 1390°C (2534°F). This is the temperature at which the vapor pressure of the liquid NaBr equals the external pressure. At this temperature, the liquid NaBr will start to boil and turn into a gas. The boiling point of a substance is influenced by various factors such as pressure, temperature, and intermolecular forces.
Sodium Bromide Melting Point
The melting point of NaBr is 755°C (1391°F). This is the temperature at which the solid NaBr turns into a liquid. The melting point of a substance is dependent on factors such as the strength of intermolecular forces, atomic size, and crystal structure.
Sodium Bromide Density g/mL
The density of NaBr is 3.21 g/mL at room temperature. This means that one milliliter of NaBr weighs 3.21 grams. The density of a substance is a physical property that is influenced by factors such as temperature, pressure, and molecular structure.
Sodium Bromide Molecular Weight
The molecular weight of NaBr is 102.89 g/mol. This is the sum of the atomic weights of sodium and bromine, which are 22.99 g/mol and 79.90 g/mol respectively. Molecular weight is a crucial factor in chemical reactions and is often used in stoichiometry calculations.
Sodium Bromide Structure
NaBr has a crystal structure with a face-centered cubic lattice. It is made up of Na+ and Br- ions arranged in a regular pattern. The crystal structure of a compound influences its physical and chemical properties.
| Appearance | White crystalline powder |
| Specific Gravity | 3.21 g/mL |
| Color | Colorless |
| Odor | Odorless |
| Molar Mass | 102.89 g/mol |
| Density | 3.21 g/mL |
| Melting Point | 755°C (1391°F) |
| Boiling Point | 1390°C (2534°F) |
| Flash Point | Not applicable |
| Water Solubility | 90 g/L (20°C) |
| Solubility | Soluble in ethanol, acetone, and glycerol |
| Vapour Pressure | Not applicable |
| Vapour Density | Not applicable |
| pKa | 7.5 |
| pH | Neutral (7.0) |
Sodium Bromide Safety and Hazards
NaBr is generally considered safe to handle when used as directed. However, it can be harmful if ingested or if it comes into contact with the skin or eyes. It may cause skin irritation, eye irritation, and digestive tract irritation. Inhaling the dust or mist of NaBr can also cause respiratory irritation. Therefore, it is essential to wear protective gear such as gloves and goggles when handling NaBr. In case of skin or eye contact, rinse thoroughly with water for at least 15 minutes. If ingested, seek medical attention immediately. Proper storage and handling can prevent accidents and exposure to NaBr.
| Hazard Symbols | Xi – Irritant |
| Safety Description | Avoid contact with skin and eyes. Wear protective gloves and goggles. |
| UN IDs | UN 3298 |
| HS Code | 28275100 |
| Hazard Class | 6.1 |
| Packing Group | III |
| Toxicity | LD50 (oral, rat) = 2.5 g/kg; LD50 (dermal, rabbit) > 2000 mg/kg |
Sodium Bromide Synthesis Methods
Several methods can synthesize NaBr, including the reaction of hydrobromic acid with sodium hydroxide.
This method involves mixing a solution of sodium hydroxide with hydrobromic acid, which then reacts to form NaBr and water.
Another method of synthesizing NaBr is by reacting sodium carbonate with hydrobromic acid. In this process, hydrobromic acid solution reacts with sodium carbonate to produce NaBr and carbon dioxide.
Reacting sodium with bromine yields NaBr. This process involves the reaction between metallic sodium and bromine vapor in the presence of a catalyst such as iron or copper.
Another method involves the reaction between sodium sulfite and bromine. This method involves adding sodium sulfite to a bromine solution, which then reacts to form NaBr and sodium sulfate.
The reaction between sodium and hydrogen bromide gas synthesizes NaBr. In this process, molten sodium reacts with hydrogen bromide gas, which produces NaBr and hydrogen gas. Industries and research laboratories commonly use these methods to synthesize NaBr.
Sodium Bromide Uses
Sodium bromide has several uses in various industries, including:
- Photography: Used in photographic film processing as a restrainer. It helps to control the rate at which the photographic developer works, thus producing clear and sharp images.
- Oil and gas drilling: Used as a completion fluid in oil and gas drilling operations. It helps to prevent the collapse of good walls and controls the density of the drilling fluid.
- Medicinal: Used as a sedative and anti-epileptic drug. Although its usage in medicine has decreased, some veterinary applications still use it as a sedative.
- Water treatment: Used in the treatment of water as a biocide and as a disinfectant. Also used in the production of bromine and other brominated compounds.
- Chemical synthesis: Used as a source of bromide ions in the synthesis of other chemicals, such as pharmaceuticals and agrochemicals.
- Flame retardants: Used as a flame retardant in plastics and textiles.
- Animal feed: Added to animal feed as a source of bromine, which is an essential nutrient for some animals.
Questions:
Q: What is the balanced chemical equation for the synthesis of sodium bromide from sodium and bromine?
A: The balanced chemical equation for the synthesis of NaBr from sodium and bromine is 2Na + Br2 → 2NaBr.
Q: In the reaction of aluminum bromide with ionized sodium bromide, which compound is the Lewis acid?
A: In the reaction of aluminum bromide with ionized NaBr, aluminum bromide is the Lewis acid because it accepts an electron pair from the NaBr.
Q: What type of reaction takes place when fluorine reacts with sodium bromide?
A: When fluorine reacts with NaBr, a redox reaction takes place, and the products are sodium fluoride and bromine gas.
Q: What is the ratio of sodium ions to bromide ions in neutral sodium bromide?
A: The ratio of Na+ and Br- ions in neutral NaBr is 1:1, meaning there is an equal number of Na+ and Br- ions present.
Q: Which products would form if chlorine gas was bubbled through a solution of sodium bromide?
A: When chlorine gas is bubbled through a solution of NaBr, the products formed are sodium chloride and bromine gas.