Hydrochloric acid is more complicated than you think
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i. H+ in aqueous solution is synonymous with hydronium ion (H3O+).
ii. Water is in an equilibrium autoionization reaction with itself and the hydronium and hydroxide ions:
2H2O <=> H3O+ + OH-
A pH of 7 means the negative log of the hydronium ion concentration is 7. Or about 10^-7 hydronium ions per liter. This reflects that the reaction above greatly favors water in the H2O state. We tend to make such simplifications (H+ for H3O+) in order to make teaching easier, but at some point it impedes a deeper understanding of what's really going on.
The stoichiometry which factors into the definition of pH is
H_{2}O <=> H^{+} + OH^{-}
(1) H^{+}(aq) is not synonymous with H_{3}O^{+}; the former is aqueous solvated proton, the latter is hydronium ion;
(2) Moving on to the so-called "autoionization" reaction, what you mean to say is that water is self-ionizable or, more appropriately, amphoteric, i.e., is can act as an acid (in this sense, a proton donor) or a base (the hydroxide ion);
(3) The pH of 7 is an ideal and is dependent on temperature, ionic strength, and a few other things (including pressure) that do actually move us off the pH point of 7 for a so-called "neutral" solution; and finally
(4) The units are moles per liter; and hydronium vs. proton does make a difference, as proton is one hydrogen and hydronium is 3 hydrogens.
I agree that H+ in solution is going to make temporary friends with whatever it finds in abundance until it comes in contact with something it can react less irreversibly with.
To build from fundamentals, what do we know?
Naked protons really are aggressive. Yikes. H+.
Water is just protonated OH-, it's neutral. pH 7 by definition.
The more the H+ outnumbers the OH-, the more aggressive the proton action.
If you water down HCl enough the solution strength will eventually fall into the narrow band known as "measurable pH", from pH 1 (quite acidic) to pH 7 (neutral).
pH numbers higher than 7 (all the way up to 14) are alkaline, not within reach for HCl in plain water.
It's good to have NIST-traceable pH measurements from precision electrochemical readings using pH-sensitive glass electrodes with temperature compensation. This is a type of glass that has a slight change in electrical properties according to the type and strength of ions it is exposed to, highly sensitive to aqueous H+ in particular. The range of readings is highly amplified by the instrument which is then calibrated logarithmically to the pH scale using known solutions. The known pH solutions correspond to the reference H+ concentrations according to the fundamental pH equations, without dependence on electrochemical measurement themselves.
Not quite so good using the proper pH-sensitive dyes which have been discovered useful or invented over the ages. These are strong enough pigments at visible wavelengths such that they can still be detected by eye (or spectrometer) at very low concentrations, while also possessing the property of noticeably changing color wavelength in response to degree of protonation of the dye molecules. These have been around since before electrochemistry.
In non-aqueous solutions, neither the electrodes nor the dyes behave exactly like they do with aqueous work, and I don't think the protons do either. The electrodes can be extremely useful non-aqueously, but it's not actually pH we're measuring any more. Plus different solvents are naturally going to have different water contents, sometimes whether intended or not.
And there are other things besides dyes which have visible indications of aggressiveness, like polyurethane and metals of many types. Some may take longer to notice than others, but eventually you conclude, yup, this stuff has been attacked by acid.
You will find the same number of molecules of HCl per liter of water will not be nearly as aggressive as the same number of molecules per liter in some non-aqueous solvents.
At other times it will be the water itself that is required for acid behavior to be fully as expected.
The best non-aqueous mixtures for any one purpose are probably not the ones commercially available. So you should be capable of coming up with your own.
Don't try this at home.
edit: decided to add an edit just in case someone tries to test this claim
[1]https://www.usgs.gov/special-topics/water-science-school/sci...
Not all semiconductors "get more conductive as you heat them up". A counterexample is provided by heavily doped semiconductors.
Only in resistors made of semiconductors, i.e. in NTC thermistors, the resistance decreases with the temperature.
The difference between a conductor and a semiconductor is that in the former the concentration of the carriers is constant, while in the latter the concentration of the carriers can be changed by various means, e.g. by temperature, by light, by impurities, by corpuscular radiation, by electrical fields, by contact with other materials, and by other means.
In most intrinsic semiconductors, the carrier concentration increases with the temperature, therefore the resistance decreases with the temperature.
This is a valid method to determine that a material is a semiconductor, even if false negatives are possible, when a material is a semiconductor though its resistance increases with the temperature.
Chemistry's a quixotic master.
You can be penniless, having not one penny. You can be homeless- not just fewer homes but by golly none at all. You could be endlessly fearless and remain motionless when facing things that aren't harmless.
Doubtlessly, I've been tasteless in this reply.
Imagine if the prime minister was LARPing a role in the service industry asked you that when you're living in a cardboard box
It does mean that (and/or "unable to be stained").
It's also frequently an exaggeration and I doubt most people who heard "I'm penniless" or "It's endless" would think "they have zero money" or "this will continue until I die (and beyond)".
It seemed like you were making a joke until you talked about "realizing" something. So on the off chance you weren't, you should know that "___less" and "___ free" have identical meaning. The -less suffix means "present in the quantity zero", not "present in a quantity which is smaller than some unspecified other quantity".
Prescriptively, sure, maybe, why not. Descriptively? Nah. Otherwise anyone using the world "endless" would be lying because nothing can be "endless". Most people using "penniless", the same, although some people may truly be "without a penny" (depending on your definition of "having a penny" - do material assets count?)
“Stainless except for odd situations you wouldn’t normally find messing with the oxide protective layer” isn’t a very good marketing name.
Even though it is a lie, stainless does mean the absolute.
Another fun fact about "stainless steel": it's usually said to be non-magnetic: you can't stick a magnet to it. But again this isn't completely true: the lower grades are indeed magnetic, but the higher chromium-content ones are not.
Why bother with a low-chromium-content SS? Probably either cost, or performance reasons. The high-chromium alloys are more brittle.
430 is a mild stainless steel that has decent corrosion resistance, but you're not going to want to test it too hard.
304 is more common, albeit more expensive, and will hold up pretty well under most normal conditions.
Any expected prolonged exposure to salt requires 316 or better, though.
that is surprising if true..
https://chemrxiv.org/engage/chemrxiv/article-details/6353634...
[1] Note that the H+ is never alone. It's too difficult to remove that electron from the Hydrogen, so H+ is a shorthand for something more complicated.
https://en.wikipedia.org/wiki/Hydronium
oxygen has greater electronegativity than hydrogen thus oxygen takes a greater share of the electronic orbital, becoming a net positive region
I was an EE/CS major and getting A's in the two chemistry courses I took in college is one of my proudest achievements because I had to work so hard for them. Nothing about chemistry was intuitive or simple for me.
CS is much easier to grasp, the worst it really gets in undergrad is moderately difficult math.
The gastroduodenal epithelium (stomach surface) is covered by a sticky mucus layer into which bicarbonate is secreted by surface epithelial cells. This bicarbonate-mucus layer creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal gastric acid.
We only learned this in the last 20 years so it’s relatively new science
Edit: either I misread the question or it was edited
Acids destroying whatever they touch is mostly a "kiddie" version of reality. 99.9% of acids found outside of chemistry labs and industrial settings are no more dangerous or destructive (as acids) than soda pop, lime juice, or human vomit (all of which are acids).
The reason is that some far stronger and/or more dangerous acids occasionally show up in household settings. Example: "battery acid", splashed on the skin, can cause horrific & life-long damage in seconds. Teaching kids to stay far away from anything labeled "Acid" is kinda like teaching 'em not to play with fire.
In fact it's not true. For 98% suplhuric acid, you have at least 30 seconds to wash it away with just water and have no consequence at all (eyes is a different story, that's where it's actually seconds), and battery acid is only 35% or less.
And a really good stage magician can have a random audience member shoot him in the head with a loaded gun, and catch the bullet in his teeth, too. That I've heard, you don't see that trick performed too often. Because sometimes it goes horribly wrong.
> The reason is that some far stronger and/or more dangerous acids occasionally show up in household settings. Example: "battery acid", splashed on the skin, can cause horrific & life-long damage in seconds.
I had to look up "battery acid"; turns out it's sulfuric acid, which is well known to be very dangerous.
Of course, so is hydrochloric acid, which is the acid in human vomit. The destructiveness of the solution is not determined by the acid -- we use HCl because it is extremely destructive! -- it is determined by the acid's concentration.
Note that vomiting more than a normal amount (say, because you're bulimic) will cause noticeable acid damage to your teeth.
I'd say you're at the "know enough to be dangerous" phase. The destructiveness of concentrated H2SO4 (sulfuric acid) to flesh is at least as much due to its extremely exothermic hydrophilic behavior as to its low pH. Hydrofluoric acid is typically weak (pH-wise) as an acid, but is a horrific delayed-action contact poison. Concentrated nitric acid is a dangerously powerful oxidizer, or worse. Yet concentrated phosphoric acid is arguably less dangerous than propane.
[DISCLAIMER - Neither HN nor I are in any way responsible if you pop any statement in this item your empty little head, and head off in search of your very own Darwin Award. If you have no professional safety training in handling dangerous and/or highly-concentrated acids, then you should completely avoid them.]
What point are you trying to make in response to the observation "99.9% of acids found outside a lab may be no more dangerous or destructive than human vomit, but that isn't particularly meaningful since the acid in human vomit is highly dangerous and destructive"?
For a specified acid, both concentration and pH are fairly good, one-dimensional, metrics of how relatively dangerous/destructive various solutions are. (Or at least "to within household common sense". Anyone competent to cook spaghetti should understand that "10 gallons" or "boiling hot" would make the solution far worse than "3 drops" or "ice cold".)
What set me off was that your comment seemed far too close to "concentration is a good, one-dimensional, measure of how dangerous/destructive acids are." (Without the "specified acid" and "relatively" qualifiers.) That (or a similar statement with "pH" instead of "concentration") is the sort of "logical" simplification that kiddies and idiots can far too easily latch on to, when they're thinking about doing cool & dangerous things.
(So - NO, kiddies. The fact that 5% acetic acid is vinegar, which is safe to splash on your salad, does NOT make (say) 5% hydrofluoric acid safe in any way at all. Stay the hell away from the latter, unless you want to look like a cheap horror movie extra for the rest of your might-be-kinda-short life.)
> What point are you trying to make [...] 99.9% of acids found outside a lab [...] than human vomit [...]
Technically, vomit is (horribly impure) hydrochloric acid. But for household safety purposes? Any good 11-year-old babysitter can safely clean up baby barf, using only routine baby-care supplies. But handling high-molar HCl, let alone dealing with spills of the stuff? That's a completely different world.
This is consistent with the supposition that low pH is needed to kill some pathogens.
An interesting fact is that humans have a stomach pH in the scavenger range. This is consistent with the supposition that, before becoming the most successful hunters of this planet, for a long time humans had been mainly scavengers, who scared the other scavengers and predators by throwing sticks and stones, and then consumed completely the leftovers by breaking the long bones and the skulls with stones.
https://www.science.org/content/blog-post/acid-personalities