Gọi x, y là mol $Al$, $Fe$.
$\Rightarrow 27x+56y=18,5$ (1)
$n_{H_2}=\dfrac{13,44}{22,4}=0,6 mol$
$2Al+3H_2SO_4\to Al_2(SO_4)_3+3H_2$
$Fe+H_2SO_4\to FeSO_4+H_2$
$\Rightarrow 1,5x+y=0,6$ (2)
(1)(2)$\Rightarrow x=\dfrac{151}{570}; y=\dfrac{77}{380}$
$2Al+6H_2SO_4\to Al_2(SO_4)_3+3SO_2+6H_2O$
$2Fe+6H_2SO_4\to Fe_2(SO_4)_3+3SO_2+6H_2O$
$\Rightarrow n_{SO_2}=1,5x+1,5y=\dfrac{533}{760}$
$\Rightarrow V=\dfrac{533}{760}.22,4=15,7l$