Hydrogen fluoride (HF), also known as Hydrofluoric acid is a highly corrosive and toxic gas. It is commonly used in the production of aluminum and uranium. It can cause severe burns and respiratory problems.
| IUPAC Name | Hydrogen fluoride |
| Molecular Formula | HF |
| CAS Number | 7664-39-3 |
| Synonyms | Fluorane, Fluorhydric acid, Hydrofluoric acid |
| InChI | InChI=1S/HF/h1H |
Hydrogen Fluoride Properties
Hydrogen Fluoride Formula
The formula of hydrogen fluoride is HF. This means that each molecule of HF contains one atom of hydrogen and one atom of fluorine. The formula is an important factor in determining the chemical properties and behavior of a substance.
Hydrogen Fluoride Molar Mass
The molar mass of hydrogen fluoride (HF) is 20.01 g/mol. This means that one mole of HF contains 20.01 grams of the compound. The molar mass is an important factor in determining the amount of a substance in a given sample. It is also used in calculating the concentration of a solution.
HF Boiling Point
The boiling point of hydrogen fluoride is -84.6 °C. At this temperature, HF changes from a liquid to a gas. This low boiling point makes it easy to handle and transport as a gas. However, it is important to use caution when handling HF as it is highly corrosive and toxic.
Hydrogen Fluoride Melting Point
The melting point of hydrogen fluoride is -83.6 °C. This low melting point makes it easy to handle and transport as a liquid. However, it is important to use caution when handling HF as it is highly corrosive and toxic.
Hydrogen Fluoride Density g/mL
The density of hydrogen fluoride is 1.15 g/mL at standard conditions (0 °C and 1 atm). This means that one milliliter of HF weighs 1.15 grams. The density of a substance is an important factor in determining its physical properties, such as its buoyancy and viscosity.
Hydrogen Fluoride Molecular Weight
The molecular weight of hydrogen fluoride is 20.01 g/mol. This is calculated by adding the atomic weights of the elements that make up the compound, which in this case are hydrogen (1.01 g/mol) and fluorine (18.99 g/mol). Molecular weight is an important factor in determining the properties and behavior of a substance.
Hydrogen Fluoride Structure
The structure of hydrogen fluoride is linear, with the hydrogen atom bonded to the fluorine atom through a single covalent bond. This molecule has a dipole moment, which means that it has a partial positive charge on the hydrogen atom and a partial negative charge on the fluorine atom. This makes HF a polar molecule.
| Appearance | Colorless gas or fuming liquid |
| Specific Gravity | 0.991 at -40°C |
| Color | Colorless |
| Odor | Pungent |
| Molar Mass | 20.01 g/mol |
| Density | 1.15 g/mL at 0°C |
| Melting Point | -83.6 °C |
| Boiling Point | -84.6 °C |
| Flash Point | Non-flammable |
| Water Solubility | Miscible |
| Solubility | Soluble in alcohol, ether |
| Vapour Pressure | 825.3 kPa at 20°C |
| Vapour Density | 0.98 g/L at 25°C |
| pKa | 3.17 |
| pH | <1 (diluted solution) |
Hydrogen Fluoride Safety and Hazards
Hydrogen fluoride poses significant safety hazards due to its highly corrosive and toxic nature. It can cause severe burns and respiratory problems if inhaled or exposed to the skin. HF is also capable of dissolving many materials, including glass and metals, which can lead to dangerous situations. Protective equipment, such as gloves, goggles, and respiratory protection, must be worn when handling HF. In addition, it is important to store and handle HF in appropriate containers and facilities. Emergency response plans should also be in place in case of accidental releases or spills of HF.
| Hazard Symbols | Corrosive, Toxic |
| Safety Description | Keep locked up and out of reach of children. Avoid contact with skin and eyes. In case of contact, immediately flush affected area with water and seek medical attention. Do not breathe gas/fumes/vapor/spray. Use only in a well-ventilated area. Wear protective gloves/protective clothing/eye protection/face protection. |
| UN IDs | UN1052 |
| HS Code | 28111100 |
| Hazard Class | 8 |
| Packing Group | II |
| Toxicity | Highly toxic, causes severe burns and respiratory problems |
Hydrogen Fluoride Synthesis Methods
Several methods exist for synthesizing hydrogen fluoride, one of which involves heating calcium fluoride and sulfuric acid in a reactor. In this method, a reactor heats a mixture of calcium fluoride and sulfuric acid to produce hydrogen fluoride gas. The process then cools and condenses the hydrogen fluoride gas into a liquid.
Another method involves the reaction of fluorspar with concentrated sulfuric acid in a furnace. The resulting hydrogen fluoride gas is then purified and condensed into a liquid form.
The process of electrolyzing hydrofluoric acid produces hydrogen fluoride gas, which can be condensed into a liquid.
Certain chemical manufacturing processes, such as those used to produce aluminum and uranium, can produce hydrogen fluoride as a byproduct.
One should handle and produce hydrogen fluoride with great care and attention to safety due to its highly toxic and corrosive nature. Proper protective equipment and safety protocols must be in place to prevent exposure and accidents.
Hydrogen Fluoride Uses
Hydrogen fluoride is a versatile compound with a range of applications across various industries. Here are some of the common uses of hydrogen fluoride:
- Production of fluorocarbons – The production of fluorocarbons widely uses HF, which serves as a key ingredient for producing refrigerants, aerosol propellants, and foam-blowing agents.
- Petroleum refining – Used as a catalyst in the alkylation process in petroleum refining, which helps to increase the octane rating of gasoline.
- Glass etching – Used to etch glass and remove unwanted layers from glass surfaces.
- Semiconductor industry – Manufacturers use HF in the production of semiconductors and microelectronics to etch silicon wafers and eliminate undesired layers.
- Cleaning agent – Used as a cleaning agent for various industrial equipment and surfaces.
- Pharmaceuticals – Used in the synthesis of several pharmaceutical compounds.
- Chemical synthesis – Used in the synthesis of several chemicals, including fluorine, hydrofluoric acid, and several fluorine-containing compounds.
- Metal surface treatment – Used to treat metal surfaces to improve their corrosion resistance and adhesion properties.
Questions:
Q: How many double bonds are in the Lewis structure for hydrogen fluoride, HF?
A: There are no double bonds in the Lewis structure for hydrogen fluoride, HF. Instead, the molecule has a single covalent bond between the hydrogen and fluorine atoms.
Q: Is hydrogen fluoride soluble in water?
A: Yes, hydrogen fluoride is highly soluble in water, with a solubility of approximately 450 g/L at room temperature.
Q: Is hydrogen fluoride polar?
A: Yes, hydrogen fluoride is a polar molecule. The electronegativity difference between hydrogen and fluorine atoms creates a dipole moment, resulting in a partial positive charge on the hydrogen atom and a partial negative charge on the fluorine atom.
Q: Is hydrogen fluoride ionic?
A: No, hydrogen fluoride is a covalent compound. It consists of two nonmetal atoms, hydrogen, and fluorine, that share electrons to form a molecule.
Q: Is HF a strong acid?
A: Yes, HF is considered a strong acid. It ionizes completely in water to form H+ and F- ions, resulting in a high concentration of H+ ions in the solution.
Q: Is HF a weak acid?
A: No, HF is not a weak acid. It is considered a strong acid due to its high degree of ionization in water.