Hydrazoic Acid (HN3) is a highly volatile compound. It is colorless and has a pungent odor. It is used in chemical reactions and can be toxic and explosive.
| IUPAC Name | Hydrazoic acid |
| Molecular Formula | HN3 |
| CAS Number | 7782-79-8 |
| Synonyms | Azoimide, Hydrogen azide, Azotic acid, Hydronitric acid, Triazoic acid |
| InChI | InChI=1S/HN3/c1-3-2/h1H |
Hydrazoic Acid Properties
Hydrazoic Acid Formula
The chemical formula of hydrazoic acid is HN3. It consists of one hydrogen atom and three nitrogen atoms covalently bonded together. This simple formula represents the basic composition of the compound, which is crucial in understanding its properties and reactions.
Hydrazoic Acid Molar Mass
The molar mass of hydrogen azide (HN3) is approximately 43.03 grams per mole. This value is obtained by adding the atomic masses of one hydrogen atom (H) and three nitrogen atoms (N). Molar mass is essential for calculating stoichiometry in chemical reactions.
Hydrazoic Acid Boiling Point
Hydrogen azide has a relatively low boiling point, approximately 37 degrees Celsius (98.6 degrees Fahrenheit). Due to its volatile nature, it easily vaporizes into a gaseous state at moderate temperatures. Extreme caution is required when handling this compound.
Hydrazoic Acid Melting Point
The melting point of hydrogen azide is around -80 degrees Celsius (-112 degrees Fahrenheit). At this temperature, the solid compound transitions into a liquid form. Being highly reactive, its solid state requires proper storage and handling.
Hydrazoic Acid Density g/mL
The density of hydrogen azide is approximately 1.09 grams per milliliter. This value indicates its mass per unit volume, reflecting its compactness and concentration in a given space. It is a critical parameter for laboratory measurements.
Hydrazoic Acid Molecular Weight
The molecular weight of hydrogen azide (HN3) is 43.03 grams per mole. It is the sum of the atomic weights of the elements present in a single molecule of the compound. Molecular weight plays a vital role in determining its physical and chemical behavior.
Hydrazoic Acid Structure
Hydrogen azide features a linear molecular structure, consisting of three nitrogen atoms bonded in sequence with a single hydrogen atom at the end. This arrangement results in a stable yet highly reactive compound, often used in chemical synthesis.
Hydrazoic Acid Solubility
Hydrogen azide has limited solubility in water, making it a sparingly soluble compound. It can dissolve to a small extent in aqueous solutions, but its low solubility restricts its use in certain applications. Careful consideration is necessary when dealing with its aqueous form due to its toxic and explosive nature.
| Appearance | Colorless liquid |
| Specific Gravity | 1.09 g/mL |
| Color | Colorless |
| Odor | Pungent odor |
| Molar Mass | 43.03 g/mol |
| Density | 1.09 g/mL |
| Melting Point | -80 °C (-112 °F) |
| Boiling Point | 37 °C (98.6 °F) |
| Flash Point | Not applicable |
| Water Solubility | Slightly soluble |
| Solubility | Soluble in alkali and organic solvents such as alcohol, ether |
| Vapor Pressure | 23.1 mmHg at 20 °C |
| Vapor Density | 1.4 (air = 1) |
| pKa | 4.6 |
| pH | Approximately 3-4 |
Hydrazoic Acid Safety and Hazards
Hydrogen azide poses significant safety hazards. It is highly toxic and can cause severe health effects upon exposure. Inhalation of its vapors or mists can lead to respiratory irritation, dizziness, and even death. Contact with the skin or eyes may cause burns, irritation, and tissue damage. The compound is also extremely flammable and can form explosive mixtures. It reacts violently with various substances, such as metals and oxidizing agents. Proper safety measures must be followed when handling hydrogen azide, including wearing protective clothing, using adequate ventilation, and storing it in a secure manner to prevent accidents or releases into the environment.
| Hazard Symbols | Skull and crossbones, Corrosive |
| Safety Description | Highly toxic, corrosive |
| UN IDs | UN1687 |
| HS Code | 2811.29.10 |
| Hazard Class | 6.1 (Toxic substances) |
| Packing Group | II (Medium danger) |
| Toxicity | Highly toxic; can be lethal in small quantities |
Hydrazoic Acid Synthesis Methods
Various methods allow the synthesis of hydrogen azide.
One common approach involves the reaction between sodium azide (NaN3) and an acid, such as sulfuric acid (H2SO4) or hydrochloric acid (HCl). In this method, the acid mixes with sodium azide, resulting in the formation of hydrogen azide and the corresponding salt of the acid used.
Another method involves the reaction between sodium azide and an alkyl halide, such as methyl iodide (CH3I) or ethyl iodide (C2H5I). This reaction, known as the Curtius rearrangement, results in the formation of hydrogen azide as a product.
The reaction between sodium azide and nitrous acid (HNO2) produces hydrogen azide. To generate nitrous acid in situ, one typically adds sodium nitrite (NaNO2) to an acidic solution. The reaction between sodium azide and nitrous acid yields hydrogen azide.
It is important to note that the synthesis of hydrogen azide requires careful handling and appropriate safety measures. Due to its toxicity and explosive nature, the reactions should be conducted in a well-ventilated area, using proper protective equipment and following established protocols.
Each synthesis method has its advantages and limitations, and the choice of method depends on factors such as the availability of reagents, desired yield, and safety considerations. Proper understanding and expertise in handling hazardous chemicals are crucial for conducting these syntheses effectively and safely.
Hydrazoic Acid Uses
Hydrogen azide finds applications in various fields due to its unique properties. Here are some of its uses:
- Chemical Reagent: Hydrogen azide serves as a versatile chemical reagent in organic synthesis, actively participating in numerous reactions, including the synthesis of azides, which are crucial building blocks in pharmaceuticals and dyes.
- Detonators and Propellants: Manufacturers employ hydrogen azide for the production of detonators and propellants used in airbags and safety devices, benefiting from its explosive nature and rapid decomposition, which actively releases nitrogen gas, making it valuable in these applications.
- Laboratory Analysis: Analytical chemistry utilizes hydrogen azide for the active detection and determination of various elements and compounds. It actively forms complexes with specific metals, allowing their quantification using colorimetric or titration methods.
- Biochemical Research: In biochemical research, scientists actively use hydrogen azide to modify biomolecules and study their functions. It selectively reacts with certain functional groups, actively aiding in the identification and characterization of biological molecules.
- Photography: In traditional black-and-white photography, hydrogen azide actively functions as a sensitizer in emulsions, enhancing the light sensitivity of photographic films and actively leading to improved image quality.
- Corrosion Inhibitor: Industries actively employ hydrogen azide as a corrosion inhibitor for metals, particularly copper and its alloys. It actively forms a protective layer on the metal surface, actively preventing corrosion and extending the lifespan of various equipment and structures.
- Gas Generators: Hydrogen azide actively plays a role in gas generators for airbags and life-saving systems. Its rapid decomposition actively releases nitrogen gas, providing the necessary force for inflation and deployment.
Questions:
Q: Is hydrazoic acid caustic?
A: Yes, hydrazoic acid is considered caustic and can cause burns and tissue damage upon contact.
Q: Is hydrazoic acid a strong acid?
A: Yes, hydrazoic acid is classified as a strong acid, capable of completely ionizing in water to release hydronium ions.
Q: Is hydrazoic acid a ternary acid?
A: No, hydrazoic acid is not a ternary acid. Ternary acids contain three different elements (hydrogen, oxygen, and a third element), while hydrazoic acid contains only hydrogen, nitrogen, and oxygen.
Q: How many ml of 12.5 ml hydrazoic acid?
A: The question seems incomplete and requires additional information for an accurate answer.
Q: What is the correct Lewis structure for hydrazoic acid (HN3) including the formal charges, if any?
A: The correct Lewis structure for HN3 consists of a central nitrogen atom bonded to three other nitrogen atoms and a hydrogen atom. The formal charges can be determined based on the electronegativity differences.
Q: How does hydrazoic acid affect cytochrome c oxidase?
A: Hydrogen azide inhibits cytochrome c oxidase, an enzyme involved in cellular respiration, by binding to its active site and disrupting its function.
Q: What is the Ka for hydrazoic acid if 0.20 M hydrazoic acid has a pH of 3.21?
A: The Ka for hydrazoic acid can be calculated using the pH and the equation Ka = [H3O+][A-]/[HA]. More information is required to determine the Ka value.
Q: What is the oxidation state of nitrogen in hydrazoic acid (HN3)?
A: The oxidation state of nitrogen in hydrazoic acid is -1.
Q: What is the pH of a 0.15 Molar solution of HN3 if Ka = 1.8 × 10^-9?
A: The pH of a 0.15 Molar solution of HN3 can be calculated using the Ka value and the equation pH = -log10(sqrt(Ka × [HA])).
Q: How to balance N2 + H2 into HN3?
A: The balanced equation for the reaction N2 + H2 → HN3 would be 3N2 + 6H2 → 2HN3.
Q: How to calculate the Ka of HN3?
A: The Ka of HN3 can be calculated using the equilibrium concentration of products and reactants in the dissociation reaction of HN3.
Q: What is the molarity of NaN3 if the molarity of HN3 is 0.012 M?
A: The molarity of NaN3 cannot be determined without additional information or the balanced equation of the reaction between NaN3 and HN3.
Q: What is the correct Lewis structure for hydrazoic acid (HN3) including the formal charges, if any?
A: The correct Lewis structure for HN3 includes a central nitrogen atom bonded to three other nitrogen atoms and a hydrogen atom. The formal charges can be determined based on the electronegativity differences.