Question

When zinc reacts with $HN{O}_3$ (60%), the oxidation state of nitrogen changes from :

• A. $+5to+1$
• B. $+5to-3$
• C. $+5to+4$
• D. $+5to+3$

Answer 1

The correct option is C $+5to+4$

It's clear that as we decrease the concentration of nitric acid, we get more and more reduced nitrogen: in $N{O}_2$, the oxidation state of N is (+4), then it goes to zero in $N_2$ (when we use 10% strong $HN{O}_3$).