Question

In a particular redox reaction, NO2– is oxidized to NO3– and Cu2+ is reduced to Cu+ . Complete and balance the equation for this reaction in acidic solution. Phases are optional.

Answer 1

Reduction half cell:

Cu+2 + 1e- --> Cu+

Oxidation half cell:

NO2- --> NO3- + 2e-

Balance number of electrons to be same in both half reactions

Reduction half cell:

2 Cu+2 + 2e- --> 2 Cu+

Oxidation half cell:

NO2- --> NO3- + 2e-

Lets combine both the reactions.

2 Cu+2 + NO2- --> 2 Cu+ + NO3-

Balance Oxygen by adding water

2 Cu+2 + NO2- + H2O --> 2 Cu+ + NO3-

Balance Hydrogen by adding H+

2 Cu+2 + NO2- + H2O --> 2 Cu+ + NO3- + 2 H+

This is balanced chemical equation in acidic medium

Answer:

2 Cu²⁺ + NO₂^- + H₂O --> 2 Cu⁺ + NO₃^- + 2 H⁺