$FeS_{}$ + $2HCl_{}$ → $FeCl_{2}$ + $H_{2}S$
$2H_{2}S$ + $3O_{2}$ → $2H_{2}O$ + $2SO_{2}$
$SO_{2}$ + $NaOH_{}$ → $NaHSO_{3}$
$NaHSO_{3}$ + $NaOH_{}$ → $H_{2}O$ + $Na _{2}$$SO_{3}$
$Na _{2}$$SO_{3}$ + $H_{2}$$SO_{4}$ → $Na _{2}$$SO_{4}$ + $H_{2}O$ + $SO_{2}$
$2SO_{2}$ + $0_{2}$ $\frac{t^{o}}{V_{2}O_{5}}$> $2SO_{3}$
$SO_{3}$ + $H_{2}O$ → $H_{2}$$SO_{4}$
2Al + 3H2SO4 → Al2(SO4)3 + 3H2
$H_{2}$ + $S_{}$ → $H_{2}S$
$Cl_{2}$ + $H_{2}S$ → $2HCl_{}$ + $S_{}$
$S_{}$ + $O_{2}$ → $SO_{2}$
2H2O+2KMnO4+5SO2→2H2SO4+2MnSO4+K2SO4
