There is a very useful 2024 book by Dario Bressanini titled The Science of Cleaning: Use the power of chemistry to clean smarter, easier, and safer. A preview is at Google Books. He discusses what works (a lot), what is useless, and what is dangerous. His twelve chapters and their starting page numbers are:
1] Clean and Dirty, 6
2] Acids and Bases, 14
3] Limescale, 30
4] Soaps, 50
5] Detergents, 68
6] Chlorine-Based Bleach, 92
7] Oxygen-Based Bleach, 110
8] Laundry, 120
9] Dishes, 150
10] Disinfectants, 174
11] Baking Soda, 206
12] Household Surfaces, 224
One useless mixture is described in his detailed section on pages 24 to 26 titled Baking Soda and Vinegar: a mixture that makes no sense. The reaction is shown above. He says:
“Every time someone suggests mixing vinegar and baking soda to remove a stain or unblock a drain, a chemist somewhere combusts. I couldn’t say precisely when this particular craze began, but it’s definitely popular. Pick any online cleaning forum or Facebook group, then look for a video on how to unblock the sink, clean the carpet, or degrease a frying pan – or follow a few influencers or pick through the hand hints section of a modern home magazine – and it won’t be long before you begin to hear the inexorable chant in your head ‘Vinegar and baking soda, vinegar and baking soda, mix them quickly and watch the magic.’
It's a pity that not only does mixing them not work, it can even be counterproductive. I know many of you are thinking, ‘But everyone is saying it!’ Well, I’m afraid that everyone is wrong. No matter how many times we repeat something false, it doesn’t become true. As I explained above, baking soda is basic while vinegar is acidic. When mixed, they react instantly to produce water, carbon dioxide, and sodium acetate, a mildly basic substance with absolutely no cleaning properties. Likewise if you mix – in the correct quantities – two highly corrosive substances like lye and hydrochloric acid. The result is an innocuous water and sodium chloride mixture: salt water, in other words. This happens because in chemical reactions, the properties of the original substances disappear as the substances themselves no longer exist, having chemically transformed. Therefore, it makes absolutely no sense to mix substances that react with each other.
I realize, however, that it might be too flippant to dismiss vinegar and baking soda in this way. As a chemist. I’ve often wondered how such an inaccurate piece of advice could have become so popular. It wouldn’t be the first time a wholly incorrect or ineffective home or traditional remedy has propagated at such speed and with such fervor. Kitchen and cooking tips are an excellent case in point, and some of the popular claims about how to clean or keep our kitchens hygienic are so wildly inaccurate that they shouldn’t be given the time of day. Why would throwing coffee grounds down the sink help unclog it?
Anyway, the habit of mixing vinegar and baking soda is so common, and its promoters are so convinced of its effectiveness, that I decided to take a closer look. I spent a long time thinking about it until I eventually identified three reasons this urban legend has taken such a strong hold.
The first is psychological: When vinegar (or lemon juice) touches baking soda, it instantly fizzes, producing a very impressive cloud of foam and bubbles. It may look like something special is happening, but it’s still just carbon dioxide with no detergent properties. It you put it in the kitchen sink, the bubbles may drag up some of the dirt from the pipes and you may interpret this as a cleaning miracle. I’m sorry to be the bearer of bad news: It isn’t.
The second reason is the comforting knowledge that both vinegar and baking soda are edible, so they must be completely harmless. Everywhere we turn, we’re bombarded with warnings and ads fueling concerns for our health and the environment, suggesting – incorrectly and often dishonestly – that normal cleaning products, the ones ‘made of stuff with complicated names we don’t understand,’ are hazardous for our health. Conversely, there’s no denying that if you buy a product to unlock the kitchen sink, it will have a warning symbol blazoned across the label. For example, as I said earlier, lye should be used with caution, but it’s precisely its corrosiveness that enables it to unclog your sink. So if you pick up a magazine or follow an influencer and both tell you to use a much safer mix of vinegar and baking soda instead of the more dangerous lye, the temptation to believe is difficult to resist, especially if you’ve forgotten the chemistry you learned in school.
I’ve no doubt that many of you reading this will be ready to swear that your mixture ‘worked’ – that the last time you used it, it really did clean the thing you set out to clean.
This brings me to my third reason for this phenomenon, which is strictly chemical. I said earlier that vinegar and baking soda (just like lye and hydrochloric acid) cancel each other out, but only if you use the correct quantities of the two reactants. I’ll save you the calculations, but a liter of ordinary 6-percent vinegar requires exactly 84 grams of baking soda to react fully and produce a solution of water, carbon dioxide, and sodium acetate. Or, if you prefer, 100 ml of vinegar reacts fully with 8.4 grams of baking soda. After the reaction, both the baking soda and the acetic acid originally present in the vinegar no longer exist. I’m pretty certain none of the concoctions touted as the remedy of all cleaning ills contain exactly these quantities, which is the key to understanding why this mixture is believed to work miracles. If you mix less than 8.4 grams of baking soda with 100 ml of vinegar, the baking soda completely disappears when the two substances finish reacting, and all that is left is the excess acetic acid that didn’t react. Vice versa, if you add more baking soda, the acetic acid disappears and excess baking soda is left. It is the addition of the leftover, unused reactants that makes the mixture look like it is working.
There are generally two types of recipes for mixing vinegar with baking soda: hose with an overabundance of vinegar, which create a watery solution, and those with an overabundance of baking soda, where the latter is barely wetted by the vinegar to form a paste. When the leftover reactant is acetic acid, it is still active to a degree against any limescale crusting up faucets, lining pipes, or stopping water from draining properly. This is why the mixture seems to work, even if you’re only using what was left after the reaction and not the full 100 ml you started out with. You’re wasting vinegar and baking soda to create a liquid that is much less effective.
Some people even recommend making the mixture in advance and keeping it in a bottle. I hope you’re beginning to see why this makes absolutely no sense: As soon as baking soda and vinegar touch, at least one of them ceases to exist. If any cleaning is being done, it is coming from the leftover vinegar.
In the other recipes, the cleaning power comes from the abrasive properties of the baking soda, which is useful for scrubbing a crusted frying pan or removing buildup from an oven tray. Here, the amount of vinegar recommended leaves a portion of the baking soda unreacted and lightly moistened, so it can be used to scrape off the dirt. Once again, you’d be better off not wasting vinegar at all and just dampening a small amount of baking soda with water.”
Recent magazine articles also discuss why to not mix baking soda and vinegar. One by Ashley Abramson and Barbara Bellesi Zito at Apartment Therapy on July 31, 2024 is titled Why You Shouldn’t Mix Baking Soda and Vinegar for Cleaning, According to a Chemist. Another by Caroline Mullen in the New York Times – Wirecutter on September 15, 2025 is titled Please stop mixing baking soda and vinegar to make cleaning paste.
Regarding what is dangerous there is a box all about bleach on page 98 in white lettering on a dark gray background with a heading of WARNING!:
"Never, ever, EVER mix bleach with another substance unless you are 100 percent sure what will happen. You should especially avoid combining bleach with acids.
Every year, hundreds of people end up in the hospital after intentionally mixing acidic cleaning products with bleach. When bleach comes in contact with an acid, it liberates poisonous chlorine gas, which was used as a chemical weapon in WWI due to its toxicity. Unfortunately, there are a host of toilet cleaners out there that are identical in everything but color, except that some contain bleach and some contain hydrochloric acid. While cleaning the house one busy morning, you could easily finish one bottle and start using another without thinking – but the new bottle happens to contain a hydrochloric acid-based cleaner, and before you know it, you’re choking on chlorine gas.
Separating bleach and acids also means avoiding using a toilet that you’ve just poured a bleach-based product into. Urine is acidic, so if it hits the bleach, don’t be surprised when you get a whiff of gas. And don’t forget that vinegar and lemon juice are acids too. Ammonia and bleach are both frequently used around the house. While they’re equally effective cleaners on their own, when combined (which I beg you never to do), they can create a very unwelcome – not to mention highly irritating and toxic – substance called chloramine.
Bleach mixed with hydrogen peroxide (which is a weaker oxygen-based bleach) produces an instant whoosh of oxygen bubbles. On its own, oxygen is not toxic, but the fizz is so vigorous that it can easily send splashes of liquid onto your skin and eyes. Please also steer clear of bleach and ethyl alcohol mixtures, which can create a number of organic compounds – from chloroform to acetaldehyde – in varying concentrations.
So I’ll say it again: Don’t mix bleach with any cleaning product, really. Ever!”
