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I observed this reaction by playing around with vinegar and baking soda and I do not completely understand it.

Everyone knows that baking soda (sodium bicarbonate) and vinegar (acetic acid) go crazy when mixed together and the solution starts creating carbonic acid that decays into carbon dioxide thus forming bubbles, but I never saw anyone adding vinegar to a supersaturated solution of baking soda and water. So, I decided to try it myself.

To no surprise, the reaction goes very similarly to how it would with just solid sodium bicarbonate. However, I then decided to try and see what rubbing alcohol would do. So, I grabbed the 92% rubbing alcohol and added it to the mixture before adding the vinegar.

You could see the alcohol mix slowly with the supersaturated sodium bicarbonate solution. However, when the vinegar was added, well I do not really know.

I added the vinegar to the solution really slowly and some minor bubbling occurred on the top. However, the solution never started to boil up as it did before. Instead, it just sort of sat there at which point, I decided to just take it to the sink and pour it out and try some new stuff, but I accidentally gave the glass a slight bump and all of a sudden, the reaction took place and proceed very rapidly shooting the bubbles out of the volumetric glassware I was using and getting everywhere. I have done this reaction several more times and it is very repeatable, although, I do not know how the addition of alcohol makes the reaction not occur until the solution is disturbed.

The volumes used are 150mls supersaturated solutions of baking soda in water, 20mls 92% isopropyl alcohol, and 40mls of vinegar.

Any help with understanding this reaction would be greatly appreciated. The only thing I have come up with so far is that the alcohol is changing the water's ability to dissolve the baking soda and that when a slight jolt is added to the system the baking soda is dislodged out of the solution long enough for the vinegar to attack it, but that is just a guess.

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    $\begingroup$ Seems like you had two different layers that didn't mix immediately. If you cannot see this because the refractive indices are too close, add some food coloring to one of the liquids. $\endgroup$ Feb 14, 2017 at 22:36
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    $\begingroup$ I'm 99% sure that you are using the term supersaturated wrong. $\endgroup$
    – MaxW
    Feb 15, 2017 at 0:12
  • $\begingroup$ Is alcohol les dense than saturated carbonate solution and is vinegar poorly soluble in alcohol. Just guessing, maybe you could try to mix vigorously the soda and the alcohol and slowly add vinegar just after mixing. $\endgroup$
    – Milan
    Jan 11, 2020 at 1:27
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    $\begingroup$ You have created a kind of isopropanol based "Champagne", which is known it may or may not burst at opening, depending on how fine it is treated. $\endgroup$
    – Poutnik
    Jan 11, 2020 at 4:55

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