試題詳解

25. Based on the following experiments, which substance can prove to be bleaching?
(A) When chlorine is introduced into a NaOH solution with phenolphthalein, the solution immediately discolors.
(B) When a small amount of Na₂O₂ powder is added to the water with phenolphthalein, the solution first turns red and then discolors.
(C) The red color of phenolphthalein solution fades after the addition of SO₂.
(D) When SO₂ is added to an acidic solution of KMnO₄, the purple color of the solution fades.
(E) Addition of nitric acidified AgNO₃ solution to chlorine water results in white precipitate.