The Iodine Clock Reaction at Home (Vitamin C Variation)


Today I’ve decided to explore an iodine clock reaction that can be done at home with household materials The general gist of this reaction is that two colorless solutions are mixed and then after a certain period of time a sudden color change occurs There’s a lot of different variations and recipes for the iodine clock reactions, but pretty much all of them use some form of iodine and starch so today, we’re going to be doing the vitamin C variant and everything that you need is shown here as I said before the reaction is a mixture of two colorless solutions And this means we’re going to have to be making a Solution A and a Solution B Solution A requires two 1000 milligram tablets of Vitamin C, iodine tincture (tincture of iodine) , and distilled water My Iodine solution was 5% so I use 25 milliliters, but if your solution is let’s say 2% you’ll have to use 60 milliliters. If you can only find 500 milligram tablets of Vitamin C, you can just use four of those instead of two, and also try not to get the chewable tablets because that has a bunch of extra stuff in it. For Solution B, I used 0.4 grams of cornstarch 150 milliliters of 3% hydrogen peroxide and distilled water It’s important to note that in both of these solutions I use distilled water, and we shouldn’t use tap water because this can interfere with some things We start off by making Solution A and for this we need two 1000 milligram tablets of vitamin C Using the back of a spoon I try to crush the tablets You don’t have to completely powderize the tablets, but you don’t really want to have any chunks left over either The crushed pills are transferred to a suitable container and here I used the beaker, but in theory you could use anything really. On top of the powderized pills, I then poured in about 60 milliliters of distilled water This mixture is then stirred for something like 30 seconds What we’re doing here is we’re trying to dissolve the vitamin C from the tablets into the water Most of the pill though is just filler and stuff that’s not soluble in water, so don’t try to dissolve everything because it’s not going to happen After about 30 seconds of stirring, we’re left with a solution that kind of looks like this Like I said there’s a lot of insoluble stuff in the pills So to get rid of this we’re going to have to filter it off The filter system is very simple, and it’s just a couple coffee filters in a dollar store funnel. I dumped the mixture into the coffee filters and very quickly a relatively clear solution starts to come through This is going to take a little bit of time so while it’s filtering I’m going to move on to making Solution B To make Solution B, we first have to measure out a little bit of cornstarch. In the beginning of the video I said to use 0.4 grams, but it really doesn’t have to be accurate and you can just estimate based on how much you see here in the video. On top of the cornstarch I poured in about three hundred and fifty milliliters of distilled water Once the water is added, I try to mix up the cornstarch, but the solution remains pretty cloudy To try to dissolve as much cornstarch as possible the solution is placed in a microwave and heat up until boiling Although it’s clearer than before, it’s still a little too cloudy for my liking so I filter it through something like four coffee filters The solution that makes it through is a lot clearer, and it has a lot less free-floating undissolved cornstarch in it Once it’s all filtered through I remove the funnel and I turn the flask so I can see the volume markings What we do now is we add about 150 milliliters of 3% hydrogen peroxide After the peroxide is added and the solution is mixed a little bit We’re done making Solution B and we can move back to making Solution A For Solution A, the next thing that we need to do is add our iodine tincture to our vitamin C solution The iodine tincture is very dark and strongly colored but when it’s added to the vitamin C you can see that the color starts to disappear After everything’s added and the mixture is swirled, it should go back to being colorless. If this doesn’t happen it means you didn’t have enough vitamin C The color of the tincture is due to the presence of iodine or I2 but when it reacts with vitamin C, it’s converted to iodide or I- which is colorless To finish Solution A, we just top things off to about 500 milliliters Solutions A and B are now complete, so we’re done with our preparation and we can move on to the fun part To test things out, we add roughly an equal amount of Solutions A and B to a beaker and then mix it up. A sudden color change should occur, but this might actually take a little bit of time, so while we’re waiting for things to change I’m going to quickly talk about what’s happening here in Solution A we effectively have a mixture of vitamin C and colorless I- ions and in Solution B we have hydrogen peroxide and starch When Solutions A and B are mixed they actually start reacting together but it’s not just one reaction that’s occurring it’s two reactions These two reactions are competing and they kind of push each other back and forth The hydrogen peroxide wants to oxidize the I- back to colored I2 but the ascorbic acid wants to reduce it from I2 back to I- This reaction occurs really quickly and the I2 doesn’t exist for very long and it’s extremely transient Eventually though the vitamin C is consumed because we’ve included an excess of hydrogen peroxide, so I2 starts to accumulate The I2 then very quickly complexes with I- to form triiodide complex and this quickly complexes with starch This all happens extremely quickly, and we’re left with a nice blue complex of triiodide and starch The concentration of each of the reactants and the temperature of the reaction mixture will determine how long it takes for the color change to occur The color change will occur quicker if we increase the concentration of either the I- or the hydrogen peroxide and the color change will take longer if we increase the concentration of Vitamin C. On top of concentrations, we can alter temperature, so if we increase the temperature the color change will occur much quicker, and if we decrease the temperature it will take longer At the concentration and temperature that I did for this previous demonstration it took about a minute to change but for me this was a bit too long, so to speed things up I heated up my Solutions A and B in the microwave After I heated them up they were around 50 °C and instead of taking something like a minute it took something around 10 to 20 seconds Here we just have an example where Solution A is already in a beaker and I add Solution B but we mix it the whole time When the solution is being constantly stirred the color change occurs much more uniformly throughout the whole thing We can also do the classic demonstration where the solutions are mixed back and forth and then we slowly pour the solution from one into the other When we do this the color should in theory change at the exact same time throughout all of the liquid. Here it kind of looks like it wasn’t all at the same time, but it still is pretty close So here’s a demonstration that I kind of thought might be cool where it looks like we make some instant coke So just like all of the other demonstrations. We pour Solution A or B in and then we follow it with the other Solution Pouring one solution into the other actually mixes things pretty well, but just to make sure that everything was thoroughly mixed I shook it around a little The color change occurs pretty quickly after I place the coke bottle back down Some of you might be wondering why I have my phone with the timer running in the background nd this is actually because I don’t want people to claim that this is fake or something I wait a few minutes, and then I place a glass on the side, and I pour out our freshly synthesized coke The color is actually surprisingly close to that of actual coke you know except for the purple cloud that comes off when I pour it into the glass What’s interesting is this is from another run, and I didn’t wait long enough before pouring the solution, and you can actually see it’s green you have to actually wait a little bit for the peroxide to convert more I- to I2 which has a slight brown color in water So for now, that’s all I really have to say about this method for the iodine clock reaction. I really want to do this method because it’s very easily done at home But I don’t think the color change is as fast and instantaneous as some of the other methods I’ve also decided to revisit and redo my previous iodine clock reaction video, and I’ve already filmed that and that should be up eventually I haven’t posted a video in a while, and it’s not because I’m slacking, it’s because I’ve kind of gone on a rampage and filmed a bunch So as usual a big, thanks goes out to all of my supporters on Patreon, but I have to give a very special thanks to everyone who donated five dollars or more Like I said in a previous video I kind of have too many $5 supporters to realistically read out each of your names But just know that I still love you all

100 thoughts on “The Iodine Clock Reaction at Home (Vitamin C Variation)

  1. Is there a way to make the iodine clock reaction but you can drink it after it changed? Or even a way that it taste as coke?

  2. I just saw a video called how to turn water into Pepsi by Stuart Edge. is this the process he used? if so why would the people say it does taste like Pepsi?

  3. Does anyone know how to change the dark blue back to clear?  I saw a demonstration where another liquid is added after the iodine clock reaction and the water turned back to clear.  I can't figure out what liquid it was.

  4. This reaction is something like the Lugols test, it happens because the iodine gets inside of the helicoidal structure of the starch (which is a polysaccharide) , the elemental iodine color is blue , so that's why you get that color

  5. If I was a chemistry teacher in high school I'd have so much fun demonstrating this to students. This would blow their mind…

  6. Hi! NileRed! Thanks for the fun video!

    May I ask I use pure Vitamin C powder and Potassium Iodide(KI) instead of the C tablet and iodine tincture,
    how much grams each do I use for the solution A?

    The place I live only have 1% iodine tincture in pharmacy…

  7. Can I keep the two solutions for a longer time (i.e. A month or so)? And can the blue-black final solution be disposed of via a regular kitchen sink?
    Thanks in advance

  8. i'd like to see this put into one of those soda streams, could really probably prank people on facebook into believing you found the secret recipe for coke

  9. Everyone probably always complements your chemistry skills, and they are impressive. I would like to point out that your video editing and video skills in general alongside your oddly calm and sarcastic narration is really what makes your videos.

  10. I tried this but the last part (turning to dark) did not work. How sensitive is this to impurities such as droplets of tapwater or mixing them in plastic bottles instead of glass?

  11. 21 people Tryed to drink the " coke " lol my nieces and nephews absolutely loved this totally got them hooked on hanging out in the lab unfortunately almost none of our lab work is exciting to kids and not a safe environmentThanks and I love your clips !!

  12. good video but it's possible you didn't add the same amount of liquids. Because of the molecules and atoms you could have added more liquids than another.

  13. Wait – did you just pronounce the C in Ascorbic Acid?! 😲 Come on buddy, you're better than that, your just adding to the illiteracy myth… 😧

  14. I pray for the Time that some Large Beverage Co. starts 2 offer Healthy choices to everyday consumers.It would be great to see
    something like this in our local store outlets. That would B a nice start to stop & reverse many unhealthy directions that seem to be running rampant in current Iarge suppliers of drink & food choices.Alot of the readily avail.choices have proven negative Health implications ! Cut the crap-please .

  15. Is the stuff safe to drink and does it taste like coke because I saw someone do it and I wonder if it taste like Coke and is it safe to drink it was done on the magic trick from Justin flom I wanna know if he switched it out so please tell me

  16. It is kinda useless. Chemistry should serve biology. I'd rather like to know what state of Iodine is the best to consume. The vitamin C Iodine looks good. What state of Iodine is easy to incorporate into palm oil? And maybe how to get atomic Iodine from bad stuff like povidone?

  17. from someone who used to crush a lot of pills fold them into paper and roll over them a couple times with the bottom of a glass better than a mortar.

  18. You can get vit C capsules (sometimes called enteral capsules) that can be easily opened and contain no filaments nor other junk, besides vitamin C and gelatine "housing".

  19. Can't for the life of me get it tp go back to clear. I followed the instructions to the letter three times now and have always gotten a dark liquid change, but it never goes back to clear

  20. Can you change the Tincture for Potassium Iodate? What would be the correct concentration for that? Thank you 🙂

  21. Instead of using Vitamin C pills to react with I2 to produce I- , could we use thiosulfate ? Sorry for my english I’m french so let me know if there are errors in this, it’ll help me.

  22. Is the experiment still possible even though you don't filter the solution A???? and also if I can reduce the amount of ml of each variable (by ratio)???
    Thanks 😀

  23. It'd be cool to see this done again, either here or on the second channel, done in the lab method with thiosulfate. It would be a very useful addition to a lot of chem 2 classes! Most of the demos on youtube suck.

  24. I did the same thing, but it did not really work for me. It took around 2 mins to change color. Is it because I did not add enough iodine?

  25. I hope you didn't leave that dark solution inside that Coke bottle unsupervised ;> Someone could take it for a real Coke and drink it accidentally :q
    I have a question though. Two, actually:
    1. Does it react only with ascorbic acid but not citric acid? Because I wonder if it could be used to tell apart ascorbic acid from citric acid? (they're both acidic, and they have pretty similar properties)
    2. What is the role of that starch in this reaction?

  26. Maybe i'm digging in fossil but could you give me ref. for this mechianism that involvs two step recations, where I2 is intermediate product?
    Couldn't it be just Asc. Acid reacting with H2O2?

  27. What if you kept solutions a and b right above freezing, then mixed them. Hopefully creating a flash freeze. I wonder how the reaction would change while in fine ice crystal form.

  28. To me aside form all the fun sciencey colour changes,. my real interest here would be whether vitamin c reacts with lugol's to form iodide..and whether that is a permanent undesirable effect/ state.. I guess the starch has pertinence for those who may ingest a sticky bun at the same time.. is this the purpose of the video or was there some other point?

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