Nitric acid reacts with metals to form metal salts, oxides of nitrogen, and water, acting as both a strong acid and a potent oxidizing agent.
The Fundamental Reaction
Nitric acid (HNO₃) is known for being a strong acid. However, its reaction with metals is unique because it is also a strong oxidizing agent. This dual nature significantly influences the reaction products.
According to the reference provided, on reaction with metals, nitric acid forms metal salts and oxides of nitrogen and water. Unlike typical acid-metal reactions that produce hydrogen gas, nitric acid's oxidizing power often prevents hydrogen formation, instead oxidizing the hydrogen produced to water and the metal itself to a metal ion.
Key Properties of Nitric Acid
- Strong Acid: It readily donates a proton (H⁺).
- Strong Oxidizing Agent: It can gain electrons from other substances, causing them to be oxidized (lose electrons).
Why Nitric Acid is Unique
The oxidizing ability of nitric acid is crucial. Even metals that are typically unreactive with non-oxidizing acids (like copper or silver) can react with nitric acid. The acid radical, nitrate (NO₃⁻), is reduced during the reaction, typically to various oxides of nitrogen.
Varying Outcomes: Oxides of Nitrogen
The specific oxide of nitrogen formed depends heavily on the concentration of the nitric acid and the reactivity of the metal involved. Common nitrogen oxides produced include:
- Nitrogen dioxide (NO₂), often with concentrated nitric acid.
- Nitric oxide (NO), often with dilute nitric acid reacting with more reactive metals.
- Other oxides like nitrous oxide (N₂O), or even nitrogen gas (N₂) or ammonium nitrate (NH₄NO₃) in some cases.
Summary of Reaction Products
Based on the general reaction described:
- Reactants:
- Metal
- Nitric Acid (HNO₃)
- Products:
- Metal Salt (e.g., Copper Nitrate, Zinc Nitrate)
- Oxides of Nitrogen (e.g., NO₂, NO, N₂O)
- Water (H₂O)
General Reaction Outline
| Reactant 1 | Reactant 2 | Product 1 | Product 2 | Product 3 |
|---|---|---|---|---|
| Metal | Nitric Acid | Metal Salt | Oxides of Nitrogen | Water |
Understanding this reaction is key in various chemical processes, from synthesis to etching.
