Question

Which of the following cannot decolourise the iodine solution?

• A. Excess of chlorine water
• B. Excess of $N{a}_2{S}_2{O}_3$ solution
• C. Excess of $B{r}^{-}$ solution
• D. Excess of NaOH solution

Answer 1

The correct option is C Excess of $B{r}^{-}$ solution

$I_2+aq.C{l}_2\to I{O}_3^{-}+C{l}^{-};I_2+S_2{O}_3^{2-}\to I^{-}+S_4{O}_6^{2-}{I}_2+NaOH\to NaI{O}_3+NaI{I}_2+B{r}^{-}\to \text{No reaction}$