What is hno3
Last updated: April 1, 2026
Key Facts
- Nitric acid (HNO3) is a strong acid with a pungent odor and highly corrosive properties
- Primarily produced through the Ostwald process by oxidizing ammonia over a platinum catalyst
- Approximately 70% of industrial nitric acid is used in ammonium nitrate fertilizer production
- Exhibits yellow discoloration when exposed to light due to nitrogen dioxide formation
- Used in mining, metal cleaning, organic synthesis, and various laboratory applications
Chemical Properties
Nitric acid (HNO3) is one of the strongest common acids, with a concentration of approximately 16 molar in its aqueous solution. The pure compound is a colorless to pale yellow liquid with a sharp, acrid odor. Upon exposure to light, nitric acid develops a characteristic yellow or brown discoloration due to the formation of nitrogen dioxide (NO2). This property is commonly used to identify its degradation. As a strong acid, nitric acid completely dissociates in water, making it useful in numerous industrial and laboratory applications.
Industrial Production
The primary industrial method for producing nitric acid is the Ostwald process, developed in the early 1900s. This process involves three main steps: oxidation of ammonia over a platinum catalyst, absorption of resulting nitrogen oxides in water, and separation of the acid. The process is highly efficient and represents the overwhelming majority of industrial nitric acid production worldwide. High-purity nitric acid can be further concentrated through distillation.
Primary Uses
Nitric acid has diverse industrial applications:
- Fertilizer Production (70%) - Used to manufacture ammonium nitrate, a key fertilizer component
- Metal Processing - Dissolves noble metals and used in metal etching and surface treatment
- Explosives - Component in the production of RDX, TNT, and other explosives
- Organic Synthesis - Nitration reactions in pharmaceutical and chemical manufacturing
- Laboratory Applications - Analysis, dissolution of samples, and educational demonstrations
Safety and Handling
Nitric acid is extremely hazardous and requires careful handling. The acid is highly corrosive, causing severe chemical burns on skin contact. Inhalation of nitric acid vapors can damage respiratory tissue. The chemical is classified as toxic and oxidizing, meaning it can accelerate combustion of flammable materials. Proper safety equipment including acid-resistant gloves, eyewear, and ventilation are essential. Industrial and laboratory users must follow strict safety protocols and storage procedures to prevent accidents.
Environmental Impact
Nitric acid production and use have significant environmental implications. Industrial processes release nitrogen oxides that contribute to air pollution and acid rain. Agricultural runoff from ammonium nitrate fertilizers can cause water pollution and eutrophication. Modern industrial facilities employ pollution control systems to minimize emissions, and environmental regulations govern the production, transport, and disposal of nitric acid to protect ecosystems and human health.
Related Questions
What is the difference between nitric acid and hydrochloric acid?
Both are strong acids, but nitric acid (HNO3) is an oxidizing acid used in metal processing and fertilizers, while hydrochloric acid (HCl) is non-oxidizing and primarily used in cleaning and pH adjustment. Nitric acid is more hazardous and corrosive.
Can nitric acid dissolve metals?
Yes, nitric acid is a powerful oxidizing acid that dissolves most metals except platinum, gold (in dilute form), and a few others. This property makes it essential in metal processing, refining, and analytical chemistry.
Is nitric acid used in explosives?
Yes, nitric acid is used in the production of various explosives including TNT (trinitrotoluene), RDX, and ammonium nitrate-based explosives. Its oxidizing properties make it essential in these manufacturing processes.
More What Is in Daily Life
Also in Daily Life
More "What Is" Questions
Trending on WhatAnswers
Browse by Topic
Browse by Question Type
Sources
- Wikipedia - Nitric AcidCC-BY-SA-4.0
- Britannica - Nitric AcidProprietary