Đáp án:
`17,623%`
Giải thích các bước giải:
`a.`
`Fe+2HCl->FeCl_2+H_2↑`
`n_{Fe}=(8,4)/56=0,15(mol)`
`n_{H_2}=n_{Fe}=0,15(mol)`
`V_{H_2}=0,15.22,4=3,36(l)`
`b.`
`n_{HCl}=2n_{Fe}=0,3(mol)`
`m_{HCl}=0,3.36,5=10,95(g)`
`m_{ddHCl}=10,95:10,95%=100(g)`
`c.`
`m_{ddspư}=8,4+100-0,15.2=108,1(g)`
`n_{FeCl_2}=n_{Fe}=0,15(mol)`
`C%_{ddspư}=(0,15.127)/(108,1).100=17,623%`