Zn + 2HCl ➝ ZnCl2 + H2 (1)
Mg + 2HCl ➝ MgCl2 + H2 (2)
Fe + 2HCl ➝ FeCl2 + H2 (3)
\(\Sigma n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
\(\Rightarrow\Sigma m_{H_2}=0,4\times2=0,8\left(g\right)\)
Theo PT1,2,3: \(n_{HCl}=2n_{H_2}=2\times0,4=0,8\left(mol\right)\)
\(\Rightarrow\Sigma m_{HCl}=0,8\times36,5=29,2\left(g\right)\)
Theo ĐL BTKL: \(m=1,45+29,2-0,8=29,85\left(g\right)\)