How is zinc metal oxidized, and nitrate ion reduced to give ammonium ion in aqueous by the action of nitric acid on zinc?

1 Answer
Jun 14, 2016

Answer:

In every chemical reaction mass is conserved. Here zinc metal is oxidized, and nitrogen is reduced.

Explanation:

#"Oxidation half equation"#:

#ZnrarrZn^(2+) + 2e^-# #(i)#

#"Reduction half equation"#:

#NO_3^(-) + 10H^(+)+ 8e^(-) rarrNH_4^(+) + 3H_2O(l)# #(ii)#

Check. ARE both equations balanced wth respect to mass and charge? Don't trust my arithmetic.

So #4xx(i) + (ii)# #=#

#4Zn(s) + NO_3^(-) + 10H^(+) rarr 4Zn^(2+) + NH_4^+ + 3H_2O(l)#

We could add #9xxNO_3^(-)# ions to each side to give...

#4Zn(s) + 10HNO_3(aq) rarr 4Zn(NO_3)_2 + NH_4NO_3(aq) + 3H_2O(l)#

I had the idea that cold, dilute nitric acid oxidizes zinc metal with nitrogen oxide produced, but I follow the parameters of the question.

#3Zn(s) + 8HNO_3(aq) rarr 3Zn(NO_3)_2(aq) +2NO(g)uarr + 4H_2O(l)#