$n_{H_2}=\dfrac{5,6}{22,4}=0,25mol$
$PTHH :$
$2Al+3H_2SO_4\to Al_2(SO_4)_3+3H_2↑(1)$
$Zn+H_2SO_4\to ZnSO_4+H_2↑(2)$
$Gọi\ n_{Al}=a;n_{Zn}=b(a,b>0)$
$\text{Ta có :}$
$m_{hh}=27a+65b=9,2g$
$n_{H_2}=1,5a+b=0,25mol$
$\text{Ta có hpt :}$
$\left\{\begin{matrix}
27a+65b=9,2 & \\
1,5a+b=0,25 &
\end{matrix}\right.$
$⇔\left\{\begin{matrix}
a=0,1 & \\
b=0,1 &
\end{matrix}\right.$
$⇒\%m_{Al}=\dfrac{0,1.27}{9,2}.100\%=29,35\%$
$\text{b.Theo pt (1) và (2) :}$
$n_{H_2SO_4}=1,5a+b=0,25mol$
$⇒C_{M_{H_2SO_4}}=\dfrac{0,25}{0,4}=0,625M$
$\text{c.Theo pt (1) và (2) :}$
$n_{Al_2(SO_4)_3}=0,5a=0,05mol$
$n_{ZnSO_4}=b=0,1mol$
$⇒C_{M_{Al_2(SO_4)_3}}=\dfrac{0,05}{0,4}=0,125M$
$C_{M_{ZnSO_4}}=\dfrac{0,1}{0,4}=0,25M$