# A solution of hydrogen ions with no counterions

## Main Question or Discussion Point

If I add some HCl to water then I'll have H+ ions but for every proton there'll be be a Cl- counterion. I've never heard of a solution containing only the protons. You could make one if your conjugate base reacted with a solute to form a gas. The gas bubbles out and all you're left with are the protons. Is this possible? If so can anyone gimme a real life example.

Borek
Mentor
You could make one if your conjugate base reacted with a solute to form a gas.
Think it over. What solute? What reaction? Try to give an example, not real, but just in the form of hypothetical reaction, assume your solute is - for example - compound AmBn, or anything similar.

I wonder if you will have enough time, if some smarty pants will not give you the final answer to show how bright they are...

Okay lets say I have a solution of hydrochloric acid. I add a transitional metal which coordinates chloride ions. Lets say the MCln complex is a gas at room temperature or else precipitates out of solution. Wouldn't I be left with a solution containing hydronium ions with no counterions?

Borek
Mentor
In what form do you add a transitional metal?

DrDu
If I add some HCl to water then I'll have H+ ions but for every proton there'll be be a Cl- counterion. I've never heard of a solution containing only the protons. You could make one if your conjugate base reacted with a solute to form a gas. The gas bubbles out and all you're left with are the protons. Is this possible? If so can anyone gimme a real life example.
Can you figure out how large would be the electric charge of 1 mole of isolated H+ ions?

DrDu
Thinking about it, this is possible in principle. You could consider some acid with a lipophilic anion (at least in comparison with H+). Then you would create some (very small) charge separation when putting a hydrophobic solvent on top of the aequous acid solution. That would be a chemical analogon to an np junction.

In what form do you add a transitional metal?
I was thinking a pure elemental metal so as to avoid introducing any new anions into the solution. For example boiling tin in azeotropic hydrochloric acid produces stannous chloride. Its soluble in water though so thats a bad example.

Can you figure out how large would be the electric charge of 1 mole of isolated H+ ions?
This is what I was thinking. The buildup of positive charge might prevent additional MCln molecules from forming. What you said about lipophilic conjugate bases is interesting. Would the lipophilic anions actually move into the organic layer though, thats the question. Theres only 1 real way to find out. Would you say stearic acid would work for this experiment? Maybe a shorter a chain fatty acid would be more suitable since it would be easier to deprotonate.

EDIT: Now that I think of it, the deprotonated fatty acid would act as a surfactant and turn the mixture into an emulsion wouldn't it?

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Borek
Mentor
I was thinking a pure elemental metal so as to avoid introducing any new anions into the solution.
Then you have to convert it to ions. How?

For example boiling tin in azeotropic hydrochloric acid produces stannous chloride.
Write reaction equation. Note that neither boiling nor azeotropic matters, it is just dissolving tin in hydrochloric acid.

DrDu