How to Make an Iodine Clock Reaction at Home

In this video, I'll be demonstrating how anyone can make their own iodine clock reaction with simple over-the-counter chemicals.

Household Materials Needed

  • Hydrochloric acid (for cleaning purposes)
  • Hydrogen peroxide (3%)
  • Sodium hydroxide (drain cleaner)
  • Povidone-iodine (antiseptic)
  • Cornstarch
  • Sodium thiosulphate (used as water conditioner for fish bowls, but I got mine from a children's chemistry game)

The Reactions

In the first, slow reaction seen in the video above, triiodide ion is produced:

  • H2O2 + 3 I- + 2 H+ -> I3- + 2 H2O

In the second, fast reaction, triiodide is reconverted to iodide by the thiosulfate:

  • I3- + 2 S2O32- -> 3 I- + S4O62-

The color of the solution after the reaction is a result of the complex formed between iodine and starch that has dark blue color.

Be the First to Comment

Share Your Thoughts

  • Hot
  • Latest