Discussion Forum

Consider the following list of reagents, acidified K₂Cr₂O₇, alkaline KMnO₄, CuSO₄,  H₂O₂, Cl₂, O3, FeCl₃. HNO₃ and Na₂S₂O₃. The total number of reagents that can  oxidise aqueous iodide to iodine is 

Answer:

Explanation:

Acidified   K₂Cr₂O₇, CuSO₄,  H₂O₂, Cl₂, O₃, FeCl₃. and  HNO₃  oxidise aq. iodide to iodine. Alkaline  KMnO₄   oxidise aq. iodide to IO₃^-.

  Na₂S₂O₃ is a strong reducing agent which on reaction with I₂  produces I^-

$N_{2}S_{2}O_{3}+I_{2}\rightarrow2I^{-}+N_{2}S_{4}O_{6}$

 Therefore, no reaction takes place between   Na₂S₂O₃  and iodide ion. Hence, the correct integer is (7)