(N-IIIH4)2Cr2VIO7 N20 + 4 H2O + Cr2IIIO3

This is an oxidation-reduction (redox) reaction:

2 N-III - 6 e- 2 N0 (oxidation)

2 CrVI + 6 e- 2 CrIII (reduction)

Change the oxidation states