A: $KCl$
B: $O_2$
C: $Fe(OH)_2$
D: $H_2O$
E: $Fe(OH)_3$
M: $Fe_2O_3$
PTHH:
$2KClO_3\buildrel{{t^o}}\over\to 2KCl+3O_2$
$4Fe(OH)_2+2H_2O+O_2\to 4Fe(OH)_3$
$2Fe(OH)_3\buildrel{{t^o}}\over\to Fe_2O_3+3H_2O$
$Fe_2O_3+3H_2\buildrel{{t^o}}\over\to 2Fe+3H_2O$
$2H_2+O_2\buildrel{{t^o}}\over\to 2H_2O$