Copper Oxidation by Nitric Acid
3Cu + 8HNO3(dilute) → 3Cu(NO3)2 + 2NO + 4H2O
Overview
Dilute nitric acid oxidizes copper to Cu²⁺ while the nitrate ion is reduced to nitric oxide (NO) gas. Unlike HCl or H₂SO₄(dilute), nitric acid can dissolve copper because the nitrate ion acts as the oxidizing agent. The solution turns blue from Cu(NO₃)₂ and the NO gas oxidizes in air to brown NO₂.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Copper Cu | 3 | (s) |
| Reactant | Nitric Acid HNO₃ | 8 | (aq) |
| Product | Water H₂O | 4 | (l) |
Everyday Example
Chemistry students observe this reaction as a dramatic demonstration where copper dissolves in HNO₃ with brown fumes forming above the solution.
Industrial Importance
Copper dissolution in nitric acid is used in analytical chemistry, in copper etching for printed circuit board manufacturing, and in metal refining.
Properties
- Type
- Redox
- Reversible
- No
- Energy
- Exothermic
- ΔH
- -135.0 kJ/mol
Related Reactions
Aqua Regia Dissolving Gold
Bleaching with Sodium Hypochlorite
Cerium(IV) Reduction by Iron(II)
Chlorine Oxidation of Bromide
Chromate-Dichromate Equilibrium
Contact Process SO₂ Oxidation
Copper Displaced by Iron
Copper Patina Formation (Verdigris)
Copper Reduction of Silver Ion
Dichromate Oxidation of Ethanol
Frequently Asked Questions
What is the equation for Copper Oxidation by Nitric Acid?
The balanced equation is: 3Cu + 8HNO₃(dilute) → 3Cu(NO₃)₂ + 2NO + 4H₂O.
What type of reaction is Copper Oxidation by Nitric Acid?
Copper Oxidation by Nitric Acid is a redox reaction.
Is Copper Oxidation by Nitric Acid exothermic or endothermic?
Copper Oxidation by Nitric Acid is exothermic (releases energy). The enthalpy change (ΔH) is -135.0 kJ/mol.