Skip to main content
Chemistry LibreTexts

14.12: Iodine Clock Reaction Prep

  • Page ID
    209462
  • Materials
    • Stopwatches
    • Water baths or hotplates
    • Thermometers

     

    Chemicals
    • 1 L of 0.8-0.9 M H2O2 in water with 0.001 M H2SO4 stored in the refrigerator for stability.
    • 1.5 L of 0.05 M acetate buffer (0.05 M acetic acid and 0.05 M sodium acetate in same solution)
    • 1.5 L of 0.05 M potassium iodide
    • 1 L of 0.1% starch solution
    • 500 mL of 0.05 M sodium thiosulfate – Must be made fresh.
    • 200 mL of 1.76 g/L of (NH­­4)6Mo7O24.4H2O

     

    Instructions for making chemicals
    1. H2O2 solution – This is about 3% solution, which is what is found in the store.  I used our concentrated H2O2 solution (listed at 30%) but made diluted it 2:10 instead of 1:10 since it had been sitting around for a while, and that seemed to work fine.
    2. Starch solution – Take 10 g of starch and suspend in about 100 mL of water.  Add to 900 mL of boiling water and stir until translucent.  Cool and bottle.  Store in the refrigerator. 

     

    Waste bottles needed.

     

    SDS Info
    • Hydrogen Peroxide – Exclamation point – respiratory tract irritant; Corrosion – skin corrosion/burns; Corrosion –eye damage; Environmental – aquatic toxicity
    • Sulfuric Acid – Corrosion – Skin corrosion/burns; Corrosion – eye damage; Corrosion – Corrosive to metals
    • Acetic Acid –Flame – flammable; Corrosion – skin corrosion/burns; Corrosion –eye damage
    • Sodium Acetate – None
    • Potassium Iodide – Health hazard – Damage to organs through prolonged exposure
    • Starch – None
    • Sodium thiosulfate – None
    • Ammonium Molybdate – None
    • Was this article helpful?