$a,$
$1/CaCO_3+2HCl\xrightarrow{} CaCl_2+H_2O+CO_2↑$
$2/CaCl_2+Na_2CO_3\xrightarrow{} 2NaCl+CaCO_3↓$
$3/NaCl+H_2O\xrightarrow{điện\ phân\ dd\ không\ màng\ ngăn} 2NaOH+H_2↑+Cl_2↑$
$4/2NaOH+Cl_2\xrightarrow{} NaCl+NaClO+H_2O$
$b,$
$1/FeS+2HCl\xrightarrow{} FeCl_2+H_2S↑$
$2/2H_2S+SO_2\xrightarrow{} 3S↓+2H_2O$
$3/S+Zn\xrightarrow{t^o} ZnS$
$4/ZnS+Pb(NO_3)_2\xrightarrow{} PbS↓+Zn(NO_3)_2$
$c,$
$1/Zn+S\xrightarrow{t^o} ZnS$
$2/ZnS+2HCl\xrightarrow{} ZnCl_2+H_2S↑$
$3/2H_2S+SO_2\xrightarrow{} 3S↓+2H_2O$
$4/S+O_2\xrightarrow{t^o} SO_2$
chúc bạn học tốt!
