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So, there's a rumor going around again that, apparently if you put baking soda and hydrogen peroxide together with a little bit of Mountain Dew, it will make an impromptu glowstick. I have seen this claim go around millions of times, and as a Chemistry Tech and soon-to-be Chemist, this greatly disturbs me. Because you see, you can't trust everything you read online (said anyone with half a brain ever), and sometimes the stuff you do read online can be very, very dangerous. As someone with a chemistry background and plenty of (sometimes painful) experience with strong acids and bases, I notice things, things that could be dangerous, things that people without my background wouldn't know - because honestly, did you pay attention in Chemistry class in High School? Chances are, probably not. But at the very least you should know that acids and bases will burn your skin, and badly.
As a result, I feel the need to point out that this pernicious rumor about the Mountain Dew glowstick is not only false (it was even debunked by Snopes!), but extremely dangerous. So put on your goggles and button up your lab coats, because science is about to get weird (in a safe way, of course).
First of all, I will point out this - please, people, do not trust everything you see online. The above claim is 100% true, and shit like this gets people killed and severely injured. NEVER, EVER follow instructions to make something like this from online if you don’t know first thing about chemicals, you can seriously hurt yourself even if you know what you’re doing!
Now for the science. Hydrogen peroxide, chemical formula H2O2, is a base/is alkaline and is the simplest of a group of compounds called peroxides. They’re called that because these compounds are very rich in oxygen (per- = saturated, lots of; oxide = oxygen is attached to it). These compounds are usually oxidizers, and hydrogen peroxide is a damn strong one if you don’t dilute it first. Oxidizing agents generally accept electrons, and the opposite, reducing agents, donate them. We also call them proton acceptors and proton donors, since they also make good bases and acids respectively. A good way to remember Oxidation and Reduction in these terms is OIL RIG - Oxidation Is Loss (of a proton); Reduction Is Gain (of a proton).
This sounds like it’s harmless, but when a strong oxidizer reacts with anything, the reduction that occurs can break chemical bonds. This is the process many compounds with a double bond or C=O group undergo, such as the formation of esters. Oxygen itself is often found in many caustic, alkaline/basic chemicals, including many soaps, as the hydroxy group (-OH). This functional group is negatively charged in terms of electrons, meaning it readily gives a proton which makes it a good oxidizer and a good base. Meaning that, even though hydrogen peroxide is not an acid and baking soda is a harmless neutralizing agent, the hydrogen peroxide acts as one, and the result of the reaction is a very strong, very caustic base.
This is the chemical equation for the reaction between hydrogen peroxide and baking soda:
H2O2 + 2 CHNaO3 = 2 NaOH + CO2 +H2O
H2O2 is hydrogen peroxide, and CHNaO3 is baking soda. CO2 is carbon dioxide, H2O as everyone knows is water… and NaOH is sodium hydroxide, more commonly known as lye or drain cleaner. Yes, this chemical reaction makes drain cleaner, and because sodium hydroxide is a very strong base and a lot of it is produced, the weak phosphoric acid in the little bit of Mountain Dew in the bottle will do jackall to help neutralize it. Even diluted sodium hydroxide is a hazard and can burn skin, and yes, in concentrated portions it will indeed eat through concrete. The reaction produces so much heat it can make the liquid in the bottle boiling hot in seconds, and agitating it by shaking the bottle only makes it worse because agitation speeds up the rate of a reaction, as well as making gaseous products come out of solution quicker. And since you have a sealed bottle with carbon dioxide already in it, if the reaction continues for a long time the carbon dioxide will build up, and the pressure can cause the bottle to explode. Leading to, you guessed it, NaOH-covered plastic shrapnel and boiling-hot NaOH going everywhere - on your skin, in your eyes, all over your clothes, all over the road and other people… in short, it is a disaster waiting to happen and nobody should ever do this under any circumstances, unless it is part of a chemistry lab or something and they have the proper protective equipment on. Even then, it should be done in a closed Fume Hood or with a Blast shield on to protect your face from base-coated shrapnel.
Now you might say, “Hey, Sugary, wait a minute - they put hydrogen peroxide and baking soda in toothpaste, don’t they? And hydrogen peroxide is used to clean wounds all the time!” You are correct here, but take it from me - the hydrogen peroxide you have and the kind put into toothpaste is very dilute. That means it does not produce very much NaOH, but it does produce it. Most toothpastes nowadays do not have hydrogen peroxide in them, and if they do it is not in conjunction with baking soda, since this will erode the enamel on your teeth.
If you’re still not convinced that this shit is a terribly bad, dangerous idea, here is what burns from hydrogen peroxide can look like: [x] [x] (GORE WARNING. DO NOT CLICK IF SQUEAMISH.)
And here is what burns from NaOH can look like: [x] [x] [x] [x] (SAME WARNING AS THE ABOVE. DO NOT CLICK IF SQUEAMISH.)
Bottom line? Do not fuck around with ANY chemicals, even household ones, if you do not know what you’re doing and what they will actually make.