When $\mathrm{SO}_{2}$ is passed through acidified $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ solution
When $\mathrm{SO}_{2}$ is passed through acidified $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ solution
reduction of $\mathrm{SO}_{2}$ takes place
the solution turns orange
the solution turns blue
the solution turns green
Solution
Action of acidified potassium dichromate on $\mathrm{SO}_2$:
Sulphur dioxide gas is oxidized to sulphuric acid when passed through acidified potassium dichromate solution. The colour of the solution changes from orange to green because potassium dichromate is reduced to chromic sulphate.
