Reaction of Copper with Cold Dilute HNO3
When copper (Cu) reacts with cold dilute nitric acid (HNO3), the reaction is relatively mild compared to concentrated nitric acid. Here’s a detailed breakdown of the process:
Nature of the Reaction
- Copper does not react vigorously with cold dilute HNO3.
- Instead, it undergoes a partial oxidation, leading to the formation of copper(I) nitrate (CuNO3) and nitrogen oxides (NO or NO2) as by-products.
Reaction Equation
- The general reaction can be represented as:
- 3 Cu + 8 HNO3 (dilute) → 3 Cu(NO3)2 + 2 NO + 4 H2O
Products of the Reaction
- Copper(I) Nitrate (CuNO3): This is the main product, which is a soluble salt.
- Nitric Oxide (NO): This gas is formed, which can further react with oxygen to form nitrogen dioxide (NO2) in the presence of air.
- Water (H2O): This is also produced during the reaction.
Characteristics of the Reaction
- Temperature Sensitivity: The reaction is favored at lower temperatures, making it less aggressive.
- Gas Evolution: The formation of nitrogen oxides results in the evolution of gas, which may cause bubbling.
Conclusion
- The reaction of copper with cold dilute HNO3 is a classic example of a redox reaction, where copper is oxidized and nitric acid is reduced.
- Understanding this reaction is critical in inorganic chemistry, particularly in studying how metals interact with acids.
By recognizing these key points, one can appreciate the nuances of the interaction between copper and cold dilute nitric acid.