1.
$2Fe+3Cl_2\buildrel{{t^o}}\over\to 2FeCl_3$
$FeCl_3+3KOH\to Fe(OH)_3+3KCl$
$2Fe(OH)_3\buildrel{{t^o}}\over\to Fe_2O_3+3H_2O$
$Fe_2O_3+3H_2SO_4\to Fe_2(SO_4)_3+3H_2O$
$Fe_2(SO_4)_3+3BaCl_2\to 3BaSO_4+2FeCl_3$
2.
$2Cu+O_2\buildrel{{t^o}}\over\to 2CuO$
$CuO+2HCl\to CuCl_2+H_2O$
$CuCl_2+2NaOH\to Cu(OH)_2+2NaCl$
$Cu(OH)_2\buildrel{{t^o}}\over\to CuO+H_2O$
$CuO+H_2\buildrel{{t^o}}\over\to Cu+H_2O$
$Cu+Fe_2(SO_4)_3\to CuSO_4+2FeSO_4$
3.
$4Al+3O_2\buildrel{{t^o}}\over\to 2Al_2O_3$
$Al_2O_3+3H_2SO_4\to Al_2(SO_4)_3+3H_2O$
$Al_2(SO_4)_3+3BaCl_2\to 2AlCl_3+3BaSO_4$
$AlCl_3+3AgNO_3\to 3AgCl+Al(NO_3)_3$
$Al(NO_3)_3+3KOH\to Al(OH)_3+3KNO_3$
$2Al(OH)_3\buildrel{{t^o}}\over\to Al_2O_3+3H_2O$
4.
$4Na+O_2\buildrel{{t^o}}\over\to 2Na_2O$
$Na_2O+H_2O\to 2NaOH$
$2NaOH+CO_2\to Na_2CO_3+H_2O$
$Na_2CO_3+2HCl\to 2NaCl+CO_2+H_2O$
$NaCl+AgNO_3\to AgCl+NaNO_3$