Question 20
Redox ReactionsWhat is observed when aqueous solutions of each of tetraoxosulphate (VI) acid, potassium trioxoiodate (V) and potassium iodide are mixed together?
- A.A white precipitate is formed
- B.A green precipitate is formed
- C.The mixture remains colourless
- D.The mixture turns reddish brown.
Show the answer and explanation
Answer: D (The mixture turns reddish brown.)
Explanation
In acid, iodate(V) oxidizes iodide to iodine: IO3− + 5I− + 6H+ → 3I2 + 3H2O. The iodine colours the solution reddish brown.