PTHH:
Fe + 2HCl \(\rightarrow\) FeCl2 + H2
Áp dụng định luật bảo toàn khối lượng, ta có:
\(m_{Fe}+m_{HCl}=m_{FeCl_2}+m_{H_2}\)
\(\Rightarrow\) \(m_{H_2}=\left(m_{Fe}+m_{HCL}\right)-m_{FeCl_2}\)
\(\Leftrightarrow\) \(m_{H_2}=\left(5,6+7,3\right)-12,7\)
\(\Leftrightarrow\) \(m_{H_2}=12,9-12,7\)
\(\Leftrightarrow\) \(m_{H_2}=0,2\left(g\right)\)