Question

Can you represent the reduction of dinitrogen pentoxide by dihydrogen gas?

Answer 1

`N_2O_5(g) + 8H_2(g) rarr 2NH_3(g) + 5H_2O(l)`

Explanation:

This a redox equation in which nitrogen (`N(V)`) is reduced to ammonia (`N(III)`), and zerovalent hydrogen gas (`H(0)`) is oxidized to water and ammonia (`H(I)`).

Reduction:

`N_2O_5(g) + 16H^+ + 16e^(-) rarr 2NH_3(g) + 5H_2O(l)` `(i)`

Oxidation:

`H_2(g) rarr 2H^+ + 2e^-` `(ii)`

`(i) + 8xx(ii)`

`N_2O_5(g) + 8H_2(g) rarr 2NH_3(g) + 5H_2O(l)`.

I must admit that I balanced this directly. However, formal consideration of the redox couple does give the required stoichiometry. As for any equation, both mass and charge are BALANCED. This a rather expensive way to make ammonia!