Start by identifying the OXIDATION state for each of the element:+2Fe+6S−2O4→+3Fe2−2O3++4S−2O2++6S−2O3−NOT BALANCEDOnly three of the four chemicals- FeSO4 , Fe2O3 , and SO2 are directly involved in the redox reaction.The oxidation state of iron Fe has increased from+2 in +2Fe+6S−2O4 to+3 in +3Fe2−2O3 by oneand therefore Fe is oxidized.The oxidation state of sulfur S has declined from+6 in +2Fe+6S−2O4 to+4 in +4S−2O2 by TWOAND therefore some of the sulfur atoms have been reduced.The total increases in oxidation numbers shall be the same as the sum of decreases in oxidation numbers in a balanced redox reaction.The oxidation NUMBER increases by 1 for each mole of Fe atom oxidized and decreases by 2 for each mole of S oxidized.Therefore for each mole of S reduced, two moles of Fe atoms shall be oxidized.Note that sulfur dioxide, +4S−2O2 , is the only species containing sulfur atoms of oxidation state +4 . Thus all of the reduced sulfur atoms would end up in SO2 .The number of moles of sulfur atoms reduced shall therefore equal to the number of SO2 molecules produced. This number would be slightly smaller than that of +2Fe+6S−2O4 given that sulfur atoms that were not reduced GOT eventually into +6S−2O3 .Add coefficients 2 and 1 in front of FeSO4 and SO2 , respectively:2l+2Fe+6S−2O4→+3Fe2−2O3+1l+4S−2O2++6S−2O3−NOT YET BALANCEDDeduce coefficients for the rest of the species based on the conservation of iron and sulfur atoms.2l+2Fe+6S−2O4→1l+3Fe2−2O3+1l+4S−2O2+1l+6S−2O3−BALANCEDTake coefficients " 1 " out of the expression:2lFeSO4→Fe2O3+SO2+SO3