【Magic Chemistry】01 The Wonderful Iodine Clock Reaction
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This post was last edited by Desert Fish on 2017-4-21 at 13:52
Iodine clock experiment – Reagents for the experiment: 29% hydrogen peroxide solution, malonic acid, manganese sulfate, soluble starch, potassium iodate, 1 mol/L sulfuric acid. Experimental steps: 1. Prepare Solution A: Measure 97 mL of 29% hydrogen peroxide solution and transfer it into a 250 mL volumetric flask; dilute it with distilled water to the mark to obtain a 3.6 mol/L hydrogen peroxide solution. 2. Prepare Solution B: Weigh 3.9 g of malonic acid and 0.76 g of manganese sulfate, and dissolve each in an appropriate amount of water. Additionally, 0.075 g of soluble starch was taken and dissolved in about 50 mL of boiling water. Transfer the three components into a 250 mL volumetric flask and dilute to the mark to obtain a mixed solution containing 0.15 mol/L malonic acid, 0.02 mol/L manganese sulfate, and 0.03% starch. 3. Prepare the solution C: Weigh 10.75 g of potassium iodate and dissolve it in an appropriate amount of hot water, then add 20 mL of 2 mol/L sulfuric acid solution to acidify it. Transfer to a 250 mL volumetric flask and dilute to the mark to obtain a mixed solution of 0.2 mol/L potassium iodate and 0.08 mol/L sulfuric acid. 4. The solutions from groups A, B, and C were mixed in equal volumes in a conical flask; this mixed solution contained 1.2 mol/L of hydrogen peroxide, 0.05 mol/L of malonic acid, 0.0067 mol/L of manganese sulfate, 0.067 mol/L of potassium iodate, and 0.01% starch. After mixing, the reaction solution changes from colorless to blue-violet; after a few seconds it turns back to colorless, then it turns amber and its color deepens gradually. The blue-violet color reappears again and disappears after a few seconds, repeating this cycle of periodic changes. This oscillatory reaction is also known as the “iodine clock reaction”. The oscillation period is about 8 seconds, and the repeated oscillations can last for over 10 minutes.
1. The rate of the iodine clock reaction is dependent on temperature； 2. As the room temperature drops, potassium iodate precipitates out as crystals, and it dissolves again when heated slightly. Solution A should not be left for too long, otherwise hydrogen peroxide will decompose and become ineffective, leading to the failure of the experiment ； 3. The dosage of medications must not be changed arbitrarily.
It’s amazing; I wonder if it’s dangerous or not...
I collect them over time, with the intention of creating a series to share with everyone
Explosives, are they dangerous? Weren’t those also the result of scientific experiments? Guns, which were originally meant to be a tool for competition between two foreigners, have turned into weapons for killing, completely going against the original intent of their designers.
What you say makes sense. Many things are also discovered through experiments, especially in the field of chemistry. There are also some accidents that occur during this process, and some pioneers have even sacrificed their lives for this cause, such as Gan Jiang and Mo Ye, as well as Marie Curie