Fe + 2H+ -> Fe2+ + H2
Mg + 2H+ -> Mg2+ + H2
Zn + 2H+ -> Zn2+ + H2
Fe2+ + 2OH- -> Fe(OH)2
Mg2+ + 2OH- -> Mg(OH)2
Zn2+ + 2OH- -> Zn(OH)2
Zn(OH)2 + 2OH- -> ZnO22- + 2H2O
4Fe(OH)2 + O2 -> 2Fe2O3 + 4H2O
Mg(OH)2 -> MgO + H2O
Gọi nFe = a, nMg = b và nZn = c
=> 56a + 24b + 65x = 12.9
a + b +c = 0.3
80a + 40b = 10
a = 0.05
b = 0.15
c = 0.1
=> mFe = 0.05 x 56 = 2.8g
mMg = 0.15 x 24 = 3.6g
mZn = 0.1 x 65 = 6.5g