[probe_22]

 NaSCN + Na2Cr2O7 → CO2 + NO2 + Cr2O3 + Na2SO4
any help?
the reaction medium isn't specified

[AWK]

Hint - start from reading https://www.chemicalforums.com/index.php?topic=65859.0.
Moreover - this reaction cannot be balanced.

[probe_22]

i was arguing with my mates about the role of sodium ions: they says that sodium ions are spectator ones but i sustain that they aren't because there is a different quantity of them between products and reagents. so who is right?

[AWK]

The way the reaction is written indicates that it must run in the molten state (otherwise Cr2O3 would not be formed). The oxygen can only be produced by the thermal decomposition of Na₂Cr₂O₇ to NaCrO₂. If you enter additionally NaCrO₂ on the right side of the reaction equation, the reaction can be balanced. But at a temperature of 300°C, Na₂CO₃ and NaNO₂ should form in the reaction - and this reaction can also be balanced.