Copper metal on reaction with HNO3 gets oxidized and give different by-products depending on the temperature, concentration of the acid and the copper metal undergoing oxidation.
The reaction of copper with concentrated and dilute HNO3 is as shown below:
3Cu + 8HNO3(did.) ⇒ 3Cu(NO3)2 + 2NO +4H2O
Cu + 4HNO3(conc.) ⇒ Cu(NO3)2 + 2NO2 +2H2O
Rate this question :