Equivalent weight of FeS2 in the half reaction, FeS2 → Fe2O3 + SO2 is :

FeS2 +O2 →Fe2O3 +SO2Balanced reaction is4FeS2 +11O2→2Fe2O3 +8SO21 mole of FeS2​=11/4 moles of  O2Each O− atom takes 2e− for reduction∴1 O2​ molecule takes 4e− NO. of electrons gained by O2​ =  4×114 =11∴ Number of e− lost by FeS2​=11∴ Equivalent wt  of FeS2​ in this reaction= M11