Ta có:
\(n_{Fe}=\frac{5,6}{56}=0,1\left(mol\right)\)
\(PTHH:Fe+2HCl\rightarrow FeCl_2+H_2\)
\(\Rightarrow n_{H2}=n_{Fe}=0,1\left(mol\right)\)
\(n_{HCl\left(spu\right)}=0,3-0,1.2=0,1\left(mol\right)\)
\(\Rightarrow m_{dd\left(spu\right)}=5,6+200-0,1.2=205,4\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{HCl}=\frac{0,1.36,5}{205,4}.100\%=1,78\%\\C\%_{FeCl2}=\frac{0,1.127}{205,4}.100\%=6,18\%\end{matrix}\right.\)