Nitric Acid + Copper : Reaction
- chemistsinaction
- Aug 24, 2015
- 1 min read
Copper is oxidized by concentrated Nitric acid, HNO3, to produce Cu2+ ions. The Nitric acid is reduced to nitrogen dioxide, a poisonous brown gas with an irritating odor:
Cu(s) + 4HNO3(aq) —> Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)
When the copper is first oxidized, the solution is very concentrated, and the Cu2+ product is initially coordinated to nitrate ions from the nitric acid, giving the solution first a green, and then a greenish-brownish color. When the solution is diluted with water, water molecules displace the nitrate ions in the coordinate sites around the copper ions, causing the solution to change to a blue color. In dilute nitric acid, the reaction produces nitric oxide, NO, instead:
3Cu(s) + 8HNO3(aq) —> 3Cu(NO3)2(aq) + 2NO(g) + 4H2O(l)
Credit: rudescience ;
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