K
$SO_2+BaO\rightarrow BaSO_3$$S + O_2 \xrightarrow{t^o} SO_2$
_______________________________________
$SO_2+BaO\rightarrow BaSO_3$
________________________________________
$4K_2SO_3--t^o--> K_2S+3K_2SO_4$$BaSO_3 + K_2SO_4 \rightarrow BaSO_4 + K_2SO_3$
__________________________________________
$K2O+SO_2\rightarrow K_2SO_3$$K_2S + O_2 \rightarrow K_2O +SO_2$
_______________________________________________-
$2H_2O--đp-->2H_2+O_2$$K_2SO_3 + H_2SO_4 \rightarrow K_2SO_4 + H_2O +SO_2$
________________________________________________
$BaO+H_2O\rightarrow Ba(OH)_2$$2Ba + O_2 \rightarrow 2BaO$
______________________________________________________
$Ba(OH)_2+HCL------>BaCL_2+H_2O$
_________________________________________________----
$BaCl_2+H_2SO_4\rightarrow BaSO_4+2HCl$
_______________________________________
$2FeCl_2+Cl_2\rightarrow 2FeCl_3$$Fe + 2HCl \rightarrow FeCl_2 + H_2$
_______________________________________________
$FeCl_3+Fe---------->FeCl_2$
___________________________________________________________-
$2FeCl_2 + Cl_2 \rightarrow 2FeCl_3$
____________________________________________