Question

Which of the following can convert acidified Cr2O72– to green ?

• A. SO2 / H2SO3 / H2SO4
• B. SO3 / H2SO3 / H2S
• C. SO32– / H2S / Fe2+
• D. S2O32– / SO3 / Fe3+

Answer 1

Answer: (C)

SO32– / H2S / Fe2+

Answer 2

SO2 + 2H2O $\longrightarrow$ H2SO4 + 2H

coloured matter colourless matter.