a, \(n_S=\dfrac{12,8}{32}=0,4\left(mol\right)\\ n_{O_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)
PTHH: S + O2 --to--> SO2
LTL: 0,4 < 0,5 => khí oxi dư
b, \(\left\{{}\begin{matrix}n_{SO_2}=0,4\left(mol\right)\\n_{O_2\left(pư\right)}=0,4\left(mol\right)\end{matrix}\right.\\ \Rightarrow V=\left(0,4+0,5-0,4\right).22,4=11,2\left(l\right)\)