The Strongest Acids Ever

Let's investigate the strongest acids ever!

May 16, 2023・

17 min read

From an acid that explodes at the slightest touch to one that dissolves flesh in seconds, get your safety goggles on as we delve into the strongest acids ever.

Uric

Did you know that every day you pee out 0.02 ounces of acid? It’s true! But there's no need to go panicking and checking whether your private parts are still there. When your body breaks down food, it produces a waste product called uric acid.

Most of this dissolves in your blood, before passing through the kidneys and leaving the body when it’s time to take a whizz. As excruciating as this may sound, uric acid is actually pretty tame compared to the other acids I’ve got in store for you. But before we get into it, what actually is the difference between a strong and weak acid?

Essentially, an acid is a compound containing hydrogen ions. When an acid is mixed with water, it reacts and these hydrogen ions split away from the rest of the compound, creating bubbles of hydrogen gas. This is called dissociation.

The stronger the acid, the more efficiently it can dissociate, so the more hydrogen is produced when it’s mixed with water. The rate of an acid’s dissociation is measured through something called pKa. The smaller the pKa number, the stronger the acid.

Uric acid has a pKa of 5.6, which is comparatively weak. Even so, don’t think it can’t be dangerous! If you eat too much red meat and other foods high in chemicals called purines, this can raise uric acid levels in the blood so much that your body can’t process it all.

The excess uric acid can then solidify and cluster together to form sharp microscopic crystals which build up in your joints. These mini acid daggers rub against the soft lining of your joints and are incredibly painful, leading to inflammation and swelling, a condition known as gout.

And if you thought that sounded bad, blood can carry these painful crystals to your kidneys too, where they can form kidney stones. These are horrible enough when they’re inside you, but you’ve also gotta pee them out, something I don’t even want to think about.

Acetic

Most of us love salt and vinegar flavor chips. But have you ever wondered what makes them taste so bitter? It’s because of all the acetic acid in vinegar. Acetic acid has a pKa of 4.8, making it a fair bit stronger than uric acid.

Don’t worry though, vinegar is heavily diluted with water and only about 8% is actually acid. Somewhat more off-putting, diluted acetic acid is also one of the ingredients used in descaling agents, which is the stuff you spray on kettles to remove limescale.

It’s not always kept in such low concentrations though. Over in Russia, people often preserve vegetables in it, at a whopping 70% concentration! While this does stop any microorganisms from growing on the veg, it’s also pretty damn poisonous to humans.

In fact, because the dangerous solution is usually kept in the fridge, many people have unintentionally poisoned themselves after thinking the acid filled bottle was vodka!

And trust me, you don’t want to drink this stuff. If you did, you could expect excruciating esophagus and stomach burns, along with a good helping of kidney damage. Even just breathing in the vapors can lead to chest tightness, headaches, and confusion. So, maybe just stick to storing your pickles in vinegar?

Formic

Back in the 15th century, naturalists noticed that some ant hills gave off a pungent acidic vapor. It wasn’t until the 17th century however that English naturalist, John Ray, managed to figure out what it was.

He realized some ants secreted an acid, which he was able to extract. This was formic acid, from the Latin formica, meaning ant. It turns out, many species of ant spray formic acid to either hunt prey or protect their nest from predators.

Every year, hordes of aptly named Yellow Crazy Ants use this special attack to wipe out millions of red crabs from their home on Christmas Island in the Indian Ocean. By spraying formic acid on the unfortunate crabs’ eyes and joints, the fearsome ants blind and immobilize them.

But it’s not just ants that possess this savage solution. The puss moth caterpillar sprays formic acid when threatened, and stinging nettles also hold small amounts of the substance in their hair-like outgrowths.

Fortunately, although it’s stronger than anything we’ve seen so far, formic acid still isn’t that powerful, with a pKa of 3.75. It’s actually used in a lot of wart treatments, because it dries out and removes any unwanted growths when it’s absorbed by them.

Just don’t swallow any, alright? If for some reason you did, the acidic solution would burn your mouth, throat, and stomach, and could even leave you vomiting blood. It's definitely a pretty "formicable" acid!

Hydrofluoric

If you’ve ever seen Breaking Bad, you’ll be familiar with hydrofluoric acid. Technically, it’s considered to be “weak”, with a pKa of just 3.17, but don’t let that fool you. It’s the same substance Walter White uses to dispose of people without leaving a trace.

But how can something with an acidity level so similar to formic acid be so much more dangerous? Well, hydrofluoric acid contains fluorine, a chemical element so destructive it can even dissolve glass!

Fluorine has a very strong ability to pull electrons to itself, and electrons are responsible for holding atoms together. Therefore, when fluorine touches glass, it rips the electrons from it, breaking the bonds that hold it together, and dissolving it! But it doesn’t end with glass. Hydrofluoric acid can also dissolve most metals!

Naturally, you definitely wouldn’t want to dip your fingers in it. At low concentrations, you might not even realize you’d been burnt at first, because the acid interferes with nerve function. But the fluorine will have already been absorbed into your system and begun wreaking havoc.

As well as making your heart beat so fast it can become fatal, it also attacks calcium, the mineral in your body responsible for healthy bones. And by attacks, I mean it absolutely ravages your calcium levels, to the point your bones break down and collapse.

So, what if you touched a highly concentrated solution? Well, you could wave goodbye to your hands. In fact, burns from this sinister solution only need to cover 2% of your total body surface to become fatal, that’s about the size of both palms of your hands!

Oxalic

When you were growing up, you were probably told to eat your greens. You might not have been told that many vegetables contain an acid stronger than any we’ve seen so far! It’s called oxalic acid, and with a pKa of 1.25, you might be wondering why eating a bag of spinach isn’t fatal.

Indeed, just a single tablespoon of oxalic acid is enough to put you in the dirt forever! Luckily though, you’d have to chew through more than 3 whole pounds of spinach to ingest that amount. So, unless your name’s Popeye, you’ll be fine.

But oxalic acid has more uses than just giving vegans a fright. It’s often found in cleaning solutions, and even some tooth whitening products! I wouldn’t be too quick to go out and buy this stuff for your pearly whites, though.

A study of rail truck cleaners in Norway revealed 53% of those who were heavily exposed to oxalic solutions developed kidney stones. This is because oxalic acid binds with calcium in the blood to make calcium oxalate, a crystal which can end up in the kidney and form the agonizing stones.

Unlike uric acid though, oxalic acid can lead to far more severe conditions than painful peeing. If consumed, it can give you mouth ulcers, convulsions, and even result in heart failure! And if you get it on your skin, you’ll be in for an equally bad time. Like, gangrene level bad; cracked skin, lesions, intense discoloration, and total tissue death.

Picric

With a pKa of 0.38, it’s no surprise picric acid is highly toxic; if ingested, just a small amount can cause diarrhea, vomiting, difficulty breathing, and even organ failure. But that’s not even the crazy part; if picric acid dries out, it turns into picrate salts. These are so explosive, they’ll go off with a bang at the slightest touch!

So, if any old laboratory samples accidentally dry out, bomb disposal has to be called in to destroy the explosive substance! This happened in a lab in Denmark back in 2010, so they got the picrate salts to a safe position and then it blasted.

Thanks to its insanely volatile nature, the acid was used as a shell explosive in Europe from the 1880s through until World War One. Yet even away from the battlefield, it still managed to demonstrate its devastating power.

In 1917, a French munitions ship carrying a whopping 2,300 tons of picric acid and a host of other highly explosive substances collided with another vessel at Halifax harbor, Canada. The shock of the crash set the picric acid ablaze and the burning ship was propelled onto Halifax’s shore.

Then, it exploded. The monumental blast killed over 1,800 people, injured a further 9,000, and destroyed the entire north end of the city in the biggest man-made explosion ever recorded at the time.

Nitric

Now we’re really heading into the danger zone. Explosions are scary, but how about an acid so strong it can create a literal hell cloud? Meet nitric acid, a highly volatile substance made from nitrogen dioxide and water.

As well as being a key ingredient in explosives like TNT and nitroglycerin, it also made headlines back in 2015 for all the wrong reasons. After the acid was accidentally mixed with ferric chloride, another dangerous solution, the two substances reacted and caused a huge chemical explosion at a factory in Catalonia, Spain.

Fortunately, no-one died, but a colossal toxic cloud was sent sprawling across the skies, forcing some 65,000 residents of five nearby towns to stay inside.

Exposure to the toxic vapor can cause severe burns, lung damage, blindness, and even death. So I wouldn’t be popping out for a quick snap of it. With a pKa of -1.4, this acid isn’t just explosive, it’s also very corrosive, especially in its liquid form. Just look at what it does to this penny:

As you can imagine then, this stuff is pretty horrendous if it gets in contact with your skin. Not only does it immediately cause savage burns, but it also stains the exposed area a sickly yellow.

And if you accidentally swallowed any? Well, it’d make light work of your teeth, as well as burn and ulcerate your mouth, esophagus and gastrointestinal tract. That’s your entire digestive system, from throat to butt. I’m wincing just at the thought of that horrible fate.

Sulfuric

What if I told you that every year, we produce over 280 million tons of an acid so insanely powerful it can completely dissolve a human body in just two days? You’d probably say we’re all crazy, right? We must be, because we do by producing sulfuric acid. More of this scary stuff is made each year than any other manufactured chemical.

It’s used in detergents, dyes, fabrics, and fertilizers to name a few. But its widespread use doesn’t mean it’s safe. Sulfuric acid has a pKa of -3, and though that doesn’t sound much stronger than nitric acid, it’s actually an astounding 70 times the strength! In fact, it could melt through that fancy new phone you’ve got in seconds.

So, you can imagine how painful it’d be to actually touch this stuff. As well as giving you a severe chemical burn, sulfuric acid can also cause a secondary burn. This is because it’s extremely good at drawing water out of other substances, a reaction that creates intense, burning heat as it does so.

Nothing shows these insane dehydration properties better than when you add the acid into a sugar solution. When the acid hits the solution, it immediately starts removing all of the water. When this happens, it creates carbon, which is that weird shape climbing out of the beaker in the video below:

Unsurprisingly then, if for whatever reason you happened to swallow this alarming acid, it’d have no trouble turning your stomach into a black, spongy mass too.

Hydrochloric

Considering what acid can do to the human body, it’s the last place you’d expect to find one of the world’s strongest acids, right? Well, wrong. Hydrochloric acid has a powerful pKa of -5.9, and you’ve got a load of it swirling around inside you right now! Scary as it sounds, it’s actually a component of stomach acid, and helps our digestive system break down food.

You might be wondering how it’s possible to function with a pool of corrosive acid in your gut capable of dissolving steel. Fortunately, our bodies have that one figured out for us. Our stomachs are lined with a thick layer of protective mucus which repels the acid and prevents us burning from the inside out.

Aside from helping us digest pizza though, hydrochloric acid has a whole range of other uses in everything from batteries to fireworks. But try not to swallow either of those things folks, or you could be signing your own excruciatingly painful death warrant.

One carwash worker from Brighton, England, found this out the hard way back in 2014. After drinking some of the undiluted acid, which is usually mixed with water and used to clean cars with, the terrifying effect was immediate. As well as causing intense, crippling pain, the acid was so strong it dissolved his teeth! Despite being rushed to hospital, sadly, he didn’t make it.

And as for spilling it on your skin, well, considering what this stuff does to a chicken leg in just a few hours, it won’t be pretty.

Piranha Solution

Here's some valuable advice: stay away from anything named after flesh-eating piranhas. Especially when that thing is an incredibly potent acidic solution, such as the so-called “piranha solution”.

It’s not an acid itself, but rather a mixture of concentrated sulfuric acid and hydrogen peroxide. Both are dangerous substances, but together they reach a whole new level. In fact, piranha solution is so named for its scarily impressive ability to eat through organic matter in minutes. And it can devour supposedly “indestructible” cockroaches in far less time.

As well as being ridiculously corrosive, the chemical reaction between the two substances can cause the solution to reach scolding temperatures well over 200 degrees Fahrenheit. And it can also straight up explode if it touches anything organic. So, a spillage wouldn’t just burn, it could quite literally blow you to smithereens.

Even just storing this sordid solution is risky though. It produces gas, so if kept in a closed container, pressure will build up and up until it blasts! A scientist left some piranha solution in a capped bottle in his lab, and while he was gone the container exploded, destroying everything within 10 feet of it! Nobody could enter the ravaged room for weeks after without a burning sensation in their throat.

Despite its inherent danger, the corrosivity of the liquid does make it excellent at cleaning glassware, one of its few legit uses. But if you want to keep your hands, I’d recommend sticking to soap and water.

Perchloric

Can you remember the picric acid? Seemed pretty powerful back then, didn’t it? Well, perchloric acid is its bigger, meaner, and more violent brother. With a pKa of -15.2, by now you shouldn’t need me to mention this can seriously mess you up.

Aside from its outrageously strong acidity, perchloric acid has another devastating method of destruction. When dried, it forms perchlorate salts, which are prone to exploding at the slightest touch, much like picrate salts.

However, the vapor from perchloric acid alone is enough to form highly explosive crystals if it condenses on a suitable surface. There, they’ll lie dormant until accidentally knocked, when they’ll explode, like tiny, spiky booby traps.

But the acid itself is also highly explosive. Back in 1947, the workers of a factory in Los Angeles accidentally ignited 130 gallons of the volatile substance. The subsequent explosion was so powerful it leveled the factory, wrecked 11 nearby buildings, and left a massive, 25-foot crater in its wake.

Thankfully, due to its unpredictable nature and extreme toxicity, you won’t find perchloric acid in any everyday products. However, it can be mixed with ammonia to form ammonium perchlorate, an important component of rocket fuel! Because of this, hundreds of thousands of gallons of perchloric acid are produced every year. Which is a scary thought, considering the damage just 130 gallons can do!

Magic Acid

Everyone’s heard of superheroes. But did you know there’s a separate category of acids so stupendously strong they’ve been dubbed super acids? And one of the best known is called “magic acid”.

Back in 1966, some mad scientists came back from a Christmas party and decided it’d be fun to dunk a paraffin candle into a container of the superacid. To their amazement, the candle completely dissolved before their eyes, something previously thought impossible, because of how strong paraffin is. The feat was so impressive they called it magic acid!

It’s created by mixing fluorosulfuric acid with antimony pentafluoride, both of which are far stronger on their own than the already deadly sulfuric acid. When combined however, the resulting magic acid is believed to be around a hundred billion times more powerful than sulfuric acid.

Considering spilling sulfuric acid on the skin is enough to paralyze a human, I can’t even imagine what something a hundred billion times stronger could do. It’s got fluorine in it though, which literally melts bones, so that gives us some idea!

As it’s so unbelievably dangerous, magic acid doesn’t have many practical applications. However, it is used to help break down low quality gasoline and turn it into the higher quality fuel needed by racecars. That’s really putting the “formula” into Formula One!

Fluoroantimonic Acid

Here's the bad boy you’ve been waiting for; the big one, numero uno, the GOAT. Meet fluoroantimonic acid. With a daunting pKa of -25, it’s officially the strongest acid in the whole world. Made from hydrogen fluoride and antimony pentafluoride, fluoroantimonic acid is an astronomical 100,000 times stronger than even magic acid!

As such, it’s under strict lock and key. Just one sniff of the acid’s vapors would be enough to spell game over. But if you somehow spilt even the tiniest drop on your hand, it’d be one of the worst ways to go imaginable. First, the frighteningly ferocious acid would dissolve excruciatingly through your flesh, before entering your bloodstream.

Then, fluorine from the acid would start attacking the calcium in your body, rendering it useless. Without calcium to support them, your bones would be next to go, eaten from the inside out as the rest of your body quickly disintegrates with them.

The only saving grace is that it’d be over in a matter of seconds. And fluoroantimonic acid is so volatile that it violently explodes when exposed to even the slightest trace of water. And guess what’s filled with water? Your body. So in all likelihood, you’d probably become a human firework before you had the chance to become a puddle on the floor.

Fluoroantimonic acid isn’t just a flesh eater though, it’ll ruthlessly eat its way through pretty much anything. If you’ve ever seen the movie Alien, imagine the corrosiveness of the Xenomorph’s blood. That’s what we’re dealing with.

However, there is one material hardy enough to contain this superacid and you’ve probably got it in your cupboard! Polytetrafluoroethylene or its much nicer name, Teflon. In other words, the stuff that lines the inside of non-stick frying pans!

For an acid to react with another substance, it’s got to give that substance a hydrogen ion. However, Teflon is a mega tough “superplastic”. Its electrons are held together so tightly that they physically can’t accept the hydrogen of the super acid. So, no reaction can happen, and the stubborn material doesn’t dissolve into mush!

If you were amazed at the world's strongest acids, you might want to read our article about the deadliest substances in the world. Thanks for reading!