Hydrogen cyanide is a highly toxic compound used in industries, known for its deadly effects on the respiratory system. It’s colorless, has a distinct odor, and poses significant risks to human health.
| IUPAC Name | Hydrogen Cyanide |
| Molecular Formula | HCN |
| CAS Number | 74-90-8 |
| Synonyms | Prussic acid, Formonitrile, Hydrocyanic acid, Cyanhydric acid |
| InChI | InChI=1S/CHN/c1-2/h1H |
Hydrogen Cyanide Properties
Hydrogen Cyanide Formula
The formula for hydrocyanic acid is HCN. It consists of one hydrogen atom (H) bonded to a carbon atom (C) through a triple bond, and the carbon atom is further bonded to a nitrogen atom (N). This simple molecular formula represents the composition of hydrocyanic acid.
Hydrogen Cyanide Molar Mass
The molar mass of hydrocyanic acid is approximately 27.03 grams per mole. It is calculated by adding the atomic masses of hydrogen (H), carbon (C), and nitrogen (N) present in one molecule of hydrocyanic acid.
Hydrogen Cyanide Boiling Point
Hydrocyanic acid has a boiling point of around 25.7 degrees Celsius (78.3 degrees Fahrenheit). At this temperature, hydrocyanic acid changes from a liquid state to a gaseous state, releasing toxic fumes.
Hydrogen Cyanide Melting Point
The melting point of hydrocyanic acid is about -13.4 degrees Celsius (7.9 degrees Fahrenheit). At this temperature, hydrocyanic acid transitions from a solid state to a liquid state.
Hydrogen Cyanide Density g/mL
The density of hydrocyanic acid is approximately 0.687 grams per milliliter. This density value represents the mass of hydrocyanic acid per unit volume.
Hydrogen Cyanide Molecular Weight
The molecular weight of hydrocyanic acid is approximately 27.03 grams per mole. It is determined by summing the atomic weights of its constituent elements.
Hydrogen Cyanide Structure
Hydrocyanic acid has a linear molecular structure, with the hydrogen (H) atom bonded to the carbon (C) atom, and the carbon (C) atom bonded to the nitrogen (N) atom. The triple bond between carbon and nitrogen imparts stability to the molecule.
Hydrogen Cyanide Solubility
Hydrocyanic acid is highly soluble in water. It readily dissolves in water, forming a colorless solution. This solubility allows hydrocyanic acid to easily mix with and interact with other substances in various applications and environments.
| Appearance | Colorless gas |
| Specific Gravity | 0.687 |
| Color | Colorless |
| Odor | Distinct odor |
| Molar Mass | 27.03 g/mol |
| Density | 0.687 g/mL |
| Melting Point | -13.4°C (-7.9°F) |
| Boiling Point | 25.7°C (78.3°F) |
| Flash Point | -17.8°C (0°F) |
| Water Solubility | Miscible in water |
| Solubility | Soluble in organic solvents such as ether and ethyl alcohol |
| Vapor Pressure | 500 mmHg at 20°C |
| Vapor Density | 0.95 |
| pKa | 9.3 |
| pH | 5.6 (diluted hydrocyanic acid) |
Hydrogen Cyanide Safety and Hazards
Hydrocyanic acid poses significant safety hazards and should be handled with extreme caution. It is highly toxic when inhaled, ingested, or absorbed through the skin. Exposure to hydrocyanic acid can lead to severe respiratory distress, cardiac arrest, and even death. It is important to ensure proper ventilation and use personal protective equipment when working with or around hydrocyanic acid. Additionally, the compound is flammable and can form explosive mixtures with air. Storage should be in tightly sealed containers away from ignition sources. Emergency protocols, such as providing immediate medical attention and evacuating affected areas, should be in place to mitigate the risks associated with hydrocyanic acid exposure.
| Hazard Symbols | Skull and crossbones |
| Safety Description | Highly toxic; handle with extreme caution |
| UN IDs | UN1051 (Hydrocyanic acid) |
| HS Code | 2811.11.00 |
| Hazard Class | 6.1 (Poisonous substances) |
| Packing Group | I (Great danger) |
| Toxicity | Extremely toxic; can be lethal even in small quantities |
Hydrogen Cyanide Synthesis Methods
Various methods can synthesize hydrocyanic acid.
One common method is the Andrussow process. In this process, the catalysts platinum or rhodium facilitate the reaction of ammonia (NH₃) and methane (CH₄) with oxygen (O₂) to synthesize hydrocyanic acid. The reaction takes place at high temperatures, typically around 1000-1200°C. The methane acts as a reducing agent, converting oxygen to water (H₂O), while ammonia provides the nitrogen source. The resulting mixture undergoes a series of reactions, leading to the formation of hydrocyanic acid (HCN) and water vapor.
Another method of hydrocyanic acid synthesis is the BMA process. It involves the reaction of methane (CH₄) with ammonia (NH₃) in the presence of a catalyst, such as copper or nickel, at high temperatures. This process generates hydrocyanic acid as well as other byproducts.
The Andrussov-Noddack process produces hydrocyanic acid by reacting sodium cyanide (NaCN) with a strong acid, such as sulfuric acid (H₂SO₄).
It’s worth mentioning that hydrocyanic acid is a highly toxic compound, and its synthesis should be carried out with great care in well-equipped facilities, following appropriate safety protocols. The utilization of specialized equipment, proper ventilation, and adherence to safety guidelines are crucial to ensure the well-being of personnel involved in the synthesis process.
Hydrogen Cyanide Uses
Hydrocyanic acid finds application in various industries due to its unique properties. Here are some of its uses:
- Chemical Manufacturing: Hydrocyanic acid plays a crucial role in synthesizing several significant chemicals, including adiponitrile (a key component in nylon production), methyl methacrylate (used for acrylic plastics), and sodium cyanide (employed in gold extraction).
- Pharmaceuticals: The production of pharmaceuticals, such as vitamins, synthetic amino acids, and certain antibiotics, relies on hydrocyanic acid.
- Fumigation: Industries employ hydrocyanic acid as a fumigant to control pests, especially in enclosed spaces like greenhouses, ship cargo holds, and grain storage facilities.
- Metal Plating: Metalworking industries utilize hydrocyanic acid for electroplating processes to provide a protective layer on metal surfaces.
- Polymer Manufacturing: Hydrocyanic acid actively participates in the production of synthetic fibers, rubber, and resins.
- Insecticides: Certain insecticides incorporate active ingredients derived from hydrocyanic acid to ensure effective pest control in agriculture and forestry.
- Laboratory Reagent: Hydrocyanic acid serves as a reagent in various chemical reactions and laboratory procedures.
- Mining: In gold and silver mining, hydrocyanic acid acts as a chemical reagent to extract precious metals from ores.
- Synthetic Rubber Production: Hydrocyanic acid serves as a raw material in the production of synthetic rubber, such as styrene-butadiene rubber (SBR).
- Dyes and Pigments: The manufacturing of dyes and pigments involves the utilization of hydrocyanic acid, contributing to their coloration properties.
While hydrocyanic acid has its uses, it is important to handle it with the utmost care due to its high toxicity. Strict safety protocols and adherence to proper handling procedures are essential to minimize risks associated with its usage.
Questions:
Q: What is hydrogen cyanide used for?
A: Hydrocyanic acid is used in chemical manufacturing, pharmaceutical production, fumigation, metal plating, insecticides, and as a laboratory reagent, among other applications.
Q: What is the chemical formula for hydrogen cyanide?
A: The chemical formula for hydrocyanic acid is HCN.
Q: What are the ‘permitted purposes’ of hydrogen cyanide?
A: ‘Permitted purposes’ of HCN include it’s approved and regulated usage in specific industrial processes, research, and other authorized applications.
Q: What is hydrogen cyanide found in?
A: Hydrocyanic acid can be found in various chemical products, industrial settings, and natural sources such as certain plants and seeds.
Q: Where can you purchase hydrogen cyanide?
A: The purchase of hydrogen cyanide is highly restricted and regulated due to its toxicity and potential misuse.
Q: What is hydrogen cyanide?
A: Hydrocyanic acid is a highly toxic and volatile compound with a distinct odor, commonly used in industrial processes.
Q: Is hydrogen cyanide polar or nonpolar?
A: Hydrocyanic acid is a polar molecule due to the presence of polar bonds and an asymmetric distribution of electron density.
Q: What word or two-word phrase best describes the shape of the hydrogen cyanide (HCN) molecule?
A: The shape of the HCN molecule is linear.
Q: What is hydrogen cyanide used for?
A: Hydrocyanic acid is used in various industries for chemical synthesis, fumigation, metal plating, insecticides, and pharmaceutical production.
Q: Has hydrogen cyanide been used in a terrorist attack?
A: Yes, HCN has been used in the past as a chemical weapon in terrorist attacks.
Q: What are some other chemical names associated with hydrogen cyanide?
A: Other chemical names associated with HCN include prussic acid, formonitrile, hydrocyanic acid, and cyanhydric acid.
Q: What is the correct Lewis dot diagram for hydrogen cyanide?
A: The correct Lewis dot diagram for HCN includes the hydrogen (H) atom bonded to the carbon (C) atom through a single bond, and the carbon (C) atom bonded to the nitrogen (N) atom through a triple bond.
Q: What is the charge on the atoms in hydrogen cyanide?
A: In HCN, the hydrogen (H) atom has a partial positive charge, the carbon (C) atom has a partial negative charge, and the nitrogen (N) atom has a partial negative charge.
Q: What does a hydrogen cyanide capsule do to you?
A: In highly regulated and controlled contexts, an HCN capsule may be used as a means of rapid and lethal self-administration, typically for covert or emergency purposes.
Q: What kind of bond is the carbon-nitrogen bond in a molecule of hydrogen cyanide (HCN)?
A: The carbon-nitrogen bond in a molecule of HCN is a triple bond.