On adding excess of chlorine water to potassium iodide solution containing little carbon tetra chloride gives first violet colour to carbon tetrachloride and then violet colour is discharged. The change in the oxidation state of iodine from initial to final compound is

Oxidation State Change of Iodine in Reaction with Chlorine Water

When excess chlorine water is added to potassium iodide solution containing a little carbon tetrachloride, the solution first shows a violet color (due to iodine dissolved in CCl₄) and then the violet color disappears. This corresponds to the oxidation of iodide ions to iodic acid.

Redox reactions involved:

Cl₂ + H₂O → 2HCl + [O]

I₂ + 5[O] → I₂O₅

I₂O₅ + H₂O → 2HIO₃

Overall: I₂ + 5Cl₂ + 6H₂O → 2HIO₃ + 10HCl

Conclusion: The oxidation state of iodine changes from -1 initially to +5 in the final iodic acid.