1) 2Zn + O2 = 2ZnO
ZnO + 2HCl = ZnCl2 + H2O
ZnCl2 + 2NaOH = Zn(OH)2 + 2NaCl
Zn(OH)2 = ZnO + H2O
2) 2Ca + O2 = 2CaO
CaO + H2O = Ca(OH)2
Ca(OH)2 + 2HCl = CaCl2 + 2H2O
CaCl2 +Na2CO3 = CaCO3 + 2NaCl
3) 4Al + 3O2 = 2Al2O3
Al2O3 +6 HCl =2 AlCl3 + 3H2O
AlCl3 + 3NaOH = Al(OH)3 + 3NaCl
Al(OH)3 + 3HNO3 = Al(NO3)3 + 3H2O
4)2 Fe + 3Cl2 = 2FeCl3
FeCl3 + 3NaOH = Fe(OH)3 + 3NaCl
2Fe(OH)3 = Fe2O3 + 3H2O
Fe2O3 + 2Al = Al2O3 +2 Fe