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Briggs-Rauscher

Materias needed: 

  1. Potassium iodate

  2. Sulfamic acid

  3. Malonic acid

  4. Manganese(II) sulfate

  5. Starch powder

  6. Hydrogen peroxide

  7. Distillied water

  8. Beaker

  9. Cylinder

  10. Weighing scale

  11. Measuring cylinder

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Gahyeon Park

Step 1

Create solution A by adding 100ml of distilled water, 1.5g of malonic acid, 0.4g of manganese (II) sulfate and 0.1g of starch. 

Step 2

Create solution B by adding 90ml of distilled water, 10ml of sulfuric acid and 4.3g of potassium iodate.

Step 3

Create solution C by adding 100ml of 10% hydrogen peroxide. 

Step 4

Add solution A and B in order and start the magnetic stirrer. As soon as it gets mixed add solution C. (Our school didn't have a magnetic stirrer so we mixed it using a glass rod.)

Result

Originally, the solution has to show 2 main colors. Yellow and blue. However, our solution only showed a color change from yellow to orange and after sometime the solution turned brick-red with gas bubbles on top. 

How did this happen?

Iodic acid and hydrogen peroxide reacts and makes iodine where the color of the solution changes from transparent to yellow. Now, the iodine and the malonic acid reacts and makes iodine ion. As iodine and iodine ion react, the color changes from yellow to blue. 

Color change equation:

          I−          +           I2              +   I-3 + Starch

(Transparent)     (Yellow color)      (Blue color)

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Overall reaction:

     IO3        +  CH2(COOH)2   +             2H2O2             ->    ICH(COOH)2    +       2O2         +   3H2O

Iodate ion  +   Malonic acid   +    Hydrogen peroxide -> Iodomalonic acid +  Oxygen gas +  Water

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