$2NaOH+Al_2O_3\rightarrow 2NaAlO_2+H_2O$$CuO;MgO:$khong phan ung
$NaAlO_2+CO_2+2H_2O\rightarrow NaHCO_3+Al(OH)_3\downarrow$
$2Al(OH)_3\overset{t^o}{\rightarrow}Al_2O_3+3H_2O$
$2Al_2O_3\overset{dpnc}{\rightarrow}4Al+3O_2$
$CuO;MgO\overset{+CO}{\rightarrow}Cu;MgO\overset{+HCl}{\rightarrow}dd MgCl_2+Cu\downarrow$
$MgCl_2\overset{dpnc}{\rightarrow}Mg+Cl_2$