3.
a) NaCl --> HCl --> Cl2 --> KClO3 --> KCl --> Cl2 --> CaOCl2
H2SO4+2NaCl→2HCl+Na2SO4
2HCl→Cl2+H2
3Cl2+6KOH→3H2O+5KCl+KClO3
3C+2KClO3→2KCl+3CO2
2H2O+2KCl→Cl2+H2+2KOH
Ca(OH)2+Cl2→CaOCl2+H2O

b) KCl --> Cl2 --> FeCl3 --> Fe(OH)3 --> FeCl3 --> AgCl
2H2O+2KCl→Cl2+H2+2KOH
3Cl2+2Fe→2FeCl3
3Ba(OH)2+2FeCl3→3BaCl2+2Fe(OH)3
3HCl+Fe(OH)3→3H2O+FeCl3
3AgNO3+FeCl3→3AgCl+Fe(NO3)3

c) Cl2 --> NaClO --> Cl2 --> CaOCl2 --> Cl2 --> KClO3 --> Cl2
Cl2+2NaOH→H2O+NaCl+NaClO
2HCl+NaClO→Cl2+H2O+NaCl
Ca(OH)2+Cl2→CaOCl2+H2O
CaOCl2+2HCl→Cl2+H2O+CaCl2
3Cl2+6KOH→3H2O+5KCl+KClO3
Br2+2KClO3→Cl2+2KBrO3

d) Cl2 --> HCl --> NaCl --> Cl2 --> NaCl --> HCl --> Cl2
Cl2+C3H8→HCl+C3H7Cl
HCl+NaOH→H2O+NaCl
2H2O+2NaCl→Cl2+H2+2NaOH
Cl2+2Na→2NaCl
H2SO4+NaCl→HCl+NaHSO4
2HCl→Cl2+H2