\(n_{Fe}=a,n_{Fe_2O_3}=b:trong.1.phần\\ Phần.I:\\ Fe_2O_3+3H_2->2Fe+3H_2O\\ n_{Fe}=a+2b=\dfrac{11,2}{56}=0,2\left(I\right)\\ Phần.II:\\ Fe+2HCl->FeCl2+H_2\\ a=\dfrac{2,24}{22,4}=0,1\\ b=0,05\\ \%m_{Fe}=\dfrac{56\cdot0,1}{56\cdot0,1+0,05\cdot160}=41,18\%\\ \Rightarrow\%m_{Fe_2O_3}=58,82\%\)