# How do you classify this reaction? 8HNO_3 (aq) + 3 Cu (s) + O_2 (g) -> 3Cu(NO_3)_2 (aq) + 4H_2O + 2NO_2 (g)

Aug 15, 2017

This is CLEARLY a redox process, which we represent by invoking electrons as virtual particles........I do not think dioxygen is a reasonable reactant.

#### Explanation:

Copper is oxidized up to cupric ion, $C {u}^{2 +}$:

$C u \left(s\right) \rightarrow C {u}^{2 +} + 2 {e}^{-}$ $\left(i\right)$

Nitrate ion $N \left(V\right)$ is REDUCED to $N {O}_{2} \left(g\right)$, $N \left(I V\right)$:

$N {O}_{3}^{-} + 2 {H}^{+} + {e}^{-} \rightarrow N {O}_{2} + {H}_{2} O$ $\left(i i\right)$

We take $\left(i\right) + 2 \times \left(i i\right)$ to give......

$C u \left(s\right) + 2 N {O}_{3}^{-} + 4 {H}^{+} + \cancel{2 {e}^{-}} \rightarrow C {u}^{2 +} + \cancel{2 {e}^{-}} + 2 N {O}_{2} + 2 {H}_{2} O$

And cancel out the common reagents......

$C u + 2 N {O}_{3}^{-} + 4 {H}^{+} \rightarrow C {u}^{2 +} + 2 N {O}_{2} + 2 {H}_{2} O$