Question

H2S → ZnS → H2S →  K2S 
                      ↑                                     
                      S → SO2 → K2SO3  → CaSO3

Answer 1

H2S+ZnO=H2O+ZnS
ZnS+2HCL=ZnCL2+H2S
H2S+2KOH=K2S+2H2O
2H2S+3O2=2S+2H2O
S+O2=SO2
SO2+2KOH=K2SO3+H2O
K2SO3+Ca(OH)2=CaSO3+2KOH