4)
Chỉ Có Al tác dụng với HCl sp tạo ra khí H2
\(n_{H_2}=\dfrac{13.44}{22.4}=0.6\left(mol\right)\)
PTHH:
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
0.4 \(\leftarrow\) 0.6 (mol)
\(Al_2O_3+HCl\rightarrow AlCl_3+H_2O\)
nAl=\(\dfrac{0.6\cdot2}{3}=0.4\left(mol\right)\)
mAl=0.4*27=10.8(g)
=)) \(m_{Al_2O_3}=31.2-10.8=20.4\left(g\right)\)
\(\left\{{}\begin{matrix}\%Al=\dfrac{10.8}{31.2}\cdot100=34.62\%\\\%Al_2O_3=\dfrac{20.4}{31.2}\cdot100=65.38\%\end{matrix}\right.\)