a) \(n_{Al_2O_3}=\dfrac{20,4}{102}=0,2\left(mol\right)\)
PTHH: Al2O3 + 6HCl ---> 2AlCl3 + 3H2O
0,2----->1,2-------->0,4
b) \(\left\{{}\begin{matrix}m_{\text{ax}it}=m_{HCl}=1,2.36,5=43,8\left(g\right)\\m_{mu\text{ố}i}=m_{AlCl_3}=0,4.133,5=53,4\left(g\right)\end{matrix}\right.\)