Question

What is actipn of acidified potassium dichromate on so2?

Answer 1

Sulphur dioxide gas (SO2) is bubbled through acidified potassium dichromate (K2Cr2O7/H+). The orange solution turns green. Colour changes: K+ in K2Cr207 is a colourless ion, and dichromate (Cr2O72-) is an orange solution. SO2 is a colourless gas, so the intial solution is orange