SO2→ H2SO4→H2S→HCL→CUCL2→ CU(NO3)2HBR→BR2→HBRO3

4) SO

2

→ H

2

SO

4

→H

2

S→HCl

→CuCl

2

→ Cu(NO

3

)

2

HBr→Br

2

→HBrO

3