4 CrVIO3 + 6 N-IIH2 3 N20 + 2 Cr2IIIO3 + 6 H2O

This is an oxidation-reduction (redox) reaction:

6 N-II - 12 e- 6 N0 (oxidation)

4 CrVI + 12 e- 4 CrIII (reduction)

NH2 is a reducing agent, CrO3 is an oxidizing agent.