Question

redox reaction question. please show all work including the half reactions.

NH3 + O2 ----> NO2- + H2O

Answer 1

NH3 + O2 ----> NO2- + H2O

split in 2

NH3 --> NO2-

O2 ----> H2O

then; balance O by adding H2O

2H2O + NH3 --> NO2-

O2 ----> 2H2O

Balance H by adding H+

2H2O + NH3 --> NO2- + 4H+

4H+ + O2 ----> 2H2O

balance charges

2H2O + NH3 --> NO2- + 4H+ + 3e- (this is oxidizing)

4e- + 4H+ + O2 ----> 2H2O (this is reducing)

balance electrons

8H2O + 4NH3 --> 4NO2- + 16H+ + 12e-

12e- + 12H+ + 3O2 ----> 6H2O

add both

8H2O + 4NH3 +12e- + 12H+ ----> 6H2O +  3O2 4NO2- + 16H+ + 12e-

cancel common terms

2H2O + 4NH3 ----> 3O2 + 4NO2- + 4H+