My initial answer is water, considering the massive canyons we have on this planet. But is that the case? Was thinking something like acid, which is definitely corrosive, but I would think it would lose its ability after it has been used in a short amount of time while it loses its corrosive properties. We could limit this to natural occurrences of liquid substances, instead of man made.
Water doesn’t create canyons by corroding, but eroding. Water dissolved limestone readily enough, but some HCL will do the same trick orders of magnitude faster. Yes, they lose potency though. I think you’re going to have to be more specific for a decent answer.
I do think some definitions of terms would be helpful.
Canyons are formed by physical abrasion. On Earth, that competition is down to wind and water (in liquid and solid forms), but the phrasing of your question eliminates everything but liquid water. I suppose there’s magma, but it tends to layer up on things rather than wear them down.
If you’re only talking chemical action, you’d also have to define what we’re corroding. Water is quite good as a general solvent, but isn’t much good with hydrocarbons. Salt water is a little more reactive than plain water. And, as mentioned, most acids and bases start off very effective and still wind up as salt water.
Plasma?
Hydrofluoric acid is pretty damn corrosive. It will dissolve glass and many metals. It has to be stored in a polyethylene container.
I assume you are taking about ionized gas. In that case, it ain’t a liquid.
I’ll second HF. It’s nasty stuff. We use it here at our carwash as a wheel cleaner, and it’s extremely effective against brake dust, even in dilute form.
We’ve already had to replace portions of our carbon-steel conveyor due to HF exposure over time. The stuff just eats metal.
Wouldn’t that harm the tires?
HF is actually a weak acid with some good flouride reactivity thrown in. That isn’t saying it isn’t a candidate. Flouride will react madly with calcium, so limestone will react. Of course it might passivate as well.
It’s really difficult to say what the answer to this would be. Anything that is really reactive will lose it’s reactivity pretty quickly on a geologic scale. Most acids will become salt water, as will most bases. Water is both an acid and a base and if your throwing in 10^9 years it will be pretty strong in both directions.
Other candidates:
Bromine: It won’t turn to water but it will evaporate fairly quickly.
Mercury: I don’t know what it’s reactivity would be with most rocks on a geologic scale, but it would certainly erode things quickly.
Fluorantimonic acid: The strongest acid known.
The factual answer to this seems to be based principally on corrosion, so it seems worth linking to something that gives an actual definition.
Whatever the answer is would seem to be, logically, whatever atom to molecule or molecule to molecule reaction can break up the latter to the greatest volumetric difference. For instance, whether 8 billion hydrogen atoms, making up a total volume of a pinhead, can break up some complex molecule like DNA such that 8 billion of those might take up the total volume of a bowling ball. Acids may or may not be the best example since they’re really more famous for chemical reactions that are impressive to humans rather than volumetrically impressive.
The blood of the toothy critters in the Alien movies. But it’s hard to find at your average hardware store.
Certainly HF (they used to write it H2F2, I don’t know why) is the most corrosive substance I have ever seen. I worked in a lab that had a glass-fronted chemical cabinet. One of the chemicals was aqueous HF in a tightly sealed wax bottle. Nonetheless, the glass front was etched from whatever escaped. Other similar cabinets had clear glass fronts, but this one was etched.
For breadth, isn’t water considered the universal solvent? Or is that referring to puzzles – IANAC.
HF doesn’t just eat metal - if you spill it on yourself it will pass right through the skin and EAT YOUR BONES.
aqua regia is pretty corrosive too.