Give an example to show the effect of concentration of nitric acid on the formation of oxidation products.

(N/A) The products of oxidation depend on the concentration of nitric acid,the nature of the metal,and the temperature of the reaction.
For dilute nitric acid:
$3 Cu + 8 HNO_3 (\text{dilute}) \rightarrow 3 Cu(NO_3)_2 + 2 NO + 4 H_2O$
For concentrated nitric acid:
$Cu + 4 HNO_3 (\text{conc.}) \rightarrow Cu(NO_3)_2 + 2 NO_2 + 2 H_2O$