a)
Mg + 2HCl --> MgCl2 + H2
2Al + 6HCl --> 2AlCl3 + 3H2
Gọi số mol Mg, Al là a, b (mol)
=> 24a + 27b = 9(1)
\(n_{H_2}=\dfrac{10,08}{22,4}=0,45\left(mol\right)\)
Theo PTHH: \(n_{H_2}=a+1,5b=0,45\) (2)
(1)(2) => a = 0,15 (mol); b = 0,2 (mol)
\(\left\{{}\begin{matrix}\%m_{Mg}=\dfrac{0,15.24}{9}.100\%=40\%\\\%m_{Al}=\dfrac{0,2.27}{9}.100\%=60\%\end{matrix}\right.\)
b) Theo PTHH: \(n_{HCl}=2.n_{H_2}=0,9\left(mol\right)\)
=> mHCl = 0,9.36,5 = 32,85 (g)
=> \(a\%=\dfrac{32,85}{400}.100\%=8,2125\%\)
