PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
2a_____4a______2a____2a (mol)
\(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
a_____2a______a_____a (mol)
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)
b______3b______b______\(\dfrac{3}{2}\)b (mol)
Ta lập HPT: \(\left\{{}\begin{matrix}2a+a+\dfrac{3}{2}b=\dfrac{13,44}{22,4}=0,6\\24\cdot2a+56a+27b=15,8\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,2\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{0,1\cdot56}{15,8}\cdot100\%=35,44\%\\\%m_{Al}=\dfrac{0,2\cdot27}{15,8}=34,18\%\\\%m_{Mg}=30,38\%\end{matrix}\right.\)
Theo các PTHH: \(n_{HCl}=2n_{H_2}=1,2\left(mol\right)\)
\(\Rightarrow m_{ddHCl}=\dfrac{1,2\cdot36,5}{200}\cdot100\%=21,9\%\)
