Giải:
a)
S + O2 -t0-> SO2↑
2SO2 + O2 -t0-> 2SO3↑
2SO3 + H2 -> H2SO4 + SO2↑
3H2SO4 + 2Al -> Al2(SO4)3 + 3H2↑
H2 + FeO -> Fe + H2O
3Fe + 2O2 -t0-> Fe3O4
b)
2Ba + O2 -> 2BaO
BaO + H2O -> Ba(OH)2
Ba(OH)2 + 2CO2 = Ba(HCO3)2
a)
\(\left(1\right)S+O_2\underrightarrow{t^o}SO_2\)
\(\left(2\right)SO_2+O_2\underrightarrow{t^o}SO_3\)
\(\left(3\right)SO_3+H_2O\rightarrow H_2SO_4\)
\(\left(4\right)2K+H_2SO_4\rightarrow K_2SO_4+H_2\uparrow\)
\(\left(5\right)FeO+H_2\rightarrow Fe+H_2O\)
\(\left(6\right)3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
\(b.\)
\(\left(1\right)2Ba+O_2\underrightarrow{t^o}2BaO\)
\(\left(2\right)BaO+H_2O\rightarrow Ba\left(OH\right)_2\)
\(\left(3\right)Ba\left(OH\right)_2+CO_2\rightarrow Ba\left(HCO_3\right)_2\)
AlCl3 
Al(OH)3
Al2O3
Al