\(4Al\left(0,4\right)+3H_2SO_4\rightarrow2Al_2\left(SO_4\right)_3+3H_2\left(0,3\right)\)
Chất rắn không tan là Ag.
\(n_{H_2}=\frac{6,72}{22,4}=0,3\)
\(\Rightarrow m_{Al}=0,4.27=10,8\)
\(\Rightarrow\%Al=\frac{10,8}{10,8+4,6}.100\%=70,13\%\)
\(\Rightarrow\%Ag=100\%-70,13\%=29,87\%\)