How come acid doesn’t eat through glass like it does everything else?

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How come acid doesn’t eat through glass like it does everything else?

In: Chemistry

This just has a lot to do with the actual ~~crystal~~ atomic structure of glass and how easy it is for the molecules in the acid to get in and break apart bonds in the glass molecule and also how willing the glass is to react with the acid. For some reason, most acids are bad at this. I don’t know the specifics myself since it was unimportant for my education in micro tech fabrication, but I *do* know that most acids that you know of actually do dissolve glass. They just aren’t very good at it. The most notable exception is hydrofluoric acid. It absolutely shreds through glass and, coincidentally, will do the same to your bones so it’s not exactly a safe chemical under normal use.

Hydrochloric acid (one you’ve probably heard of) is ~10x slower than hydrofluoric acid at eating away glass at the same concentration. And really, most other acids just do worse from then on.

The question is basically the same for any other material. In most cases, many solids really only have one acid that is particularly good at dissolving it. Not that there aren’t more than *can* do it, it’s just that there is usually a clear best.

Edit: glass isn’t crystalline (well, at least for the glass we are talking about here)

Glass is made of two things silicon and oxygen. to dissolve it you need to be able to separate these two things apart. Think of these as a husband and wife.

Their bond is quite strong as its quite a stable relationship.

Then comes the homewrecker called acid bringing their attractive ions along. Other couples are attracted to these ions more than their husband/wife therefore they dissolve. The bond in glass is too strong more most acids to break.

Except hydroflouric acid. They’re the kneau reeves of the acid world. HOT.

Edit: after a long hard think… Im leaving the typos in.

Edit2: thanks for all the awards! Was not expecting that!

All an acid means is that when you add it too water it will result in a solution with an excess of H^(+) ions. pH tells you howm many of those ions there are per mole. It doesn’t necessarily tell you anything about how reactive it is. Citric acid has a pH of around 3 but will take a while to dissolve your teeth and you can pour it on your hand to no effect.

Hydrofluoric acid has a pH between 4 and 5. Spilling it on your hand will burn it as well as it absorbing through to youer bones and beginning to dissolve them if you spilt enough of it. It will also dissolve glass.

So acidity alone doesn’t ell you the wholöe or even that much of the story. other chemistry is more important.

It does. [Etched glass](https://www.google.com/search?tbm=isch&q=etched+glass) is very common, and is generally made by using acid to eat away at the glass, while using a stencil to mask the design. For this application, they use an[ acid in cream form](https://www.amazon.com/s?k=glass+etching+cream) to make application easier. Large cities actually often have a ban against selling that stuff to minors, because graffiti writers use it to [put their tag on windows](https://upload.wikimedia.org/wikipedia/commons/6/6b/Etching_tag_chicago.jpg), which is permanent and requires replacing the whole pane of glass to remove.