Đáp án+Giải thích các bước giải:
$a,\\ n_{H_2}=\dfrac{5,6}{22,4}=0,25(mol)\\ Fe+H_2SO_4\ (l)\to FeSO_4+H_2\\ n_{Fe}=n_{H_2}=0,25(mol)\\ m_{Fe}=0,25.56=14(g)\\ m_{Cu}=26,8-14=12,8(g)\\ n_{Cu}=\dfrac{12,8}{64}=0,2(mol)\\ 2Fe+6H_2SO_4\to Fe_2(SO_4)_3+3SO_2+6H_2O\\ Cu+2H_2SO_4\to CuSO_4+SO_2+2H_2O\\ n_{Fe_2(SO_4)_3}=\dfrac{1}{2}.n_{Fe}=0,125(mol)\\ n_{CuSO_4}=n_{Cu}=0,2(mol)\\ m=0,125.400+0,2.160=82\\ n_{SO_2}=\dfrac{3}{2}.n_{Fe}+n_{Cu}=0,575(mol)\\ V=0,575.22,4=12,88(l)\\ b,\\ n_{H_2SO_4\ l}=n_{H_2}=0,25(mol)\\ n_{H_2SO_4\ bđ}=0,25.120\%=0,3(mol)\\ m_{H_2AO_4\ bđ}=0,3.98=29,4(g)\\ x=\dfrac{29,4}{200}.100\%=14,7$