$2C+O_2\rightarrow 2CO$$3CO+Fe_2O_3\rightarrow 2Fe+3CO_2$
$CO_2+Ca(OH)_2\rightarrow CaCO_3\downarrow+H_2O$
$2CO_2+Ca(OH)_2\rightarrow Ca(HCO_3)_2$
$Ca(HCO_3)_2+2NaOH\rightarrow Na_2CO_3+CaCO_3\downarrow$
$Fe+2HCl\rightarrow FeCl_2+H_2\uparrow$
$Fe_2O_3+6HCl\rightarrow 2FeCl_3+3H_2O$
$FeCl_2+2NaOH\rightarrow 2NaCl+Fe(OH)_2\downarrow$
$FeCl_3+3NaOH\rightarrow 3NaCl+Fe(OH)_3\downarrow$
$4Fe(OH)_2+O_2\overset{t^o}{\rightarrow}2Fe_2O_3+4H_2O$
$2Fe(OH)_3\rightarrow Fe_2O_3+3H_2O$