The reaction represents the first step in the manufacture of potassium dichromate from chromite ore ($FeCr_2O_4$). The ore is fused with sodium (or potassium) carbonate in the presence of free access of air (oxygen). The balanced chemical equation is: $4 FeCr_2O_4 + 8 Na_2CO_3 + 7 O_2 \rightarrow 8 Na_2CrO_4 + 2 Fe_2O_3 + 8 CO_2$

The major product 'X' is sodium chromate ($Na_2CrO_4$), which is a yellow-coloured compound. Sodium dichromate ($Na_2Cr_2O_7$) is formed in the subsequent step by acidifying the sodium chromate solution .