2Fe+6H2SO4→Fe2(SO4)3+6H2O+3SO2
10H2SO4+2Fe3O4→3Fe2(SO4)3+10H2O+SO2
Fe2(SO4)3+3BaCl2→2FeCl3+3BaSO4
BaCl2+H2SO4→BaSO4+2HCl
mH2SO4=50*49/100=24,5g
nH2SO4=24,5/98=0,25mol
nBaSO4=44,27/233=0,19mol
nSO2=nH2SO4-nBaSO4=0,06mol(bảo toàn S)
VSO2=0,06*22,4=1,344l