[Restless_Fillmore]

I'm not a student, but these seem to be undergraduate-level questions...

Some analytical laboratory methods report "dissolved hydrogen" (for an aqueous matrix).  Why is "dissolved hydrogen" not just related to a pH measurement of the H+ ion?  I know that "dissolved hydrogen" is reporting the H₂ molecules, but why would that be considered "dissolved" and not just a mixture, as it's not dissociated?


 Is it actually a mixture but is called dissolved by convention, or is it actually somehow truly "dissolved"?


Thank you.

[Borek]

Solution is a mixture, to some extent these terms are used interchangeably. It has nothing to do with the dissociation.

Why is "dissolved hydrogen" not just related to a pH measurement of the H+ ion?

Because H⁺ and H₂ are two completely different things, not related to each other in a simple, non trivial way.

[Orcio_87]

Is it actually a mixture but is called dissolved by convention, or is it actually somehow truly "dissolved"?

It is a solution, not a mixture or colloid, as H₂ particles are small enough to fulfill solution definition.

[Restless_Fillmore]

Is it actually a mixture but is called dissolved by convention, or is it actually somehow truly "dissolved"?

It is a solution, not a mixture or colloid, as H₂ particles are small enough to fulfill solution definition.

Thanks.  What is the source of "official" definitions for the field of chemistry?  Would it be the Oxford Dictionary of Chemistry, or something else?

[Borek]

What is the source of "official" definitions for the field of chemistry?

IUPAC

https://goldbook.iupac.org/terms/view/S05746#:~:text=Also%20contains%20definition%20of%3A%20solvent,substances%2C%20which%20are%20called%20solutes.

[Orcio_87]

What is the source of "official" definitions for the field of chemistry?  Would it be the Oxford Dictionary of Chemistry, or something else?

No, only IUPAC is truly official source of the definitions.

ISO standards are official source of the laboratory procedures.