FeS2 + O2--->Fe + SO42----> + Ba2+---->BaSO4
Now mol wt of BaSO4=137+32+64=233
233 gm BaSO4 has 32 gm S
so,1.43gm----------0.1964 gm S(by calculation)
Again in FeS2,64 gm S combines with 56 gm Fe
Hence 0.1964 gm S--------56 x 0.1964 / 64==0.17185 gm Fe...
Hence total wt of FeS2 in ore==0.17185+0.1964=0.36825 gm, which is almost 43.3% of the given ore.....(Ans)....