Acid theory - which ion does the donating?

[zeta101]

I understand that with an ionic acid (when in solution), either the +ve ion OR the -ve ion can be the proton donor. Are there any ways to tell which ion does the donating by just looking at the chemical structure of the acid? I'd appreciate if someone could point me in the direction of an accepted theory that I can search for on the net.

Thanks

 

[shrumeo]

your question doesn't make sense entirely

if you mean by "ionic acid" to say "strong acid"
as in one that 'completely' dissociates in water, then once it's in solution there will be protons hanging around water (H30+) and anions hanging around water

when a base comes along, it will just accept the proton
if you want to say that the original anion part of the "strong acid" was the donator then, I guess you could say that

there will be no acid that donates a proton and be left with a positive charge, it will either be negative or neutral
(if there is, that would be a weird exception that i am not aware of)

 

[ravenprp]

for your question! The ion that donates a proton in an acid is typically the hydrogen ion (H+). However, as you mentioned, in certain ionic acids, either the positively charged ion or the negatively charged ion can act as the proton donor. This is because in these cases, the bond between the hydrogen ion and the other ion is not completely ionic, but rather partially covalent. This means that the hydrogen ion can easily dissociate and donate a proton to the other ion.

To determine which ion is the proton donor in a specific acid, you can look at the electronegativity difference between the hydrogen ion and the other ion. The more electronegative ion will be the proton acceptor, while the less electronegative ion will be the proton donor.

As for a specific theory that explains this phenomenon, you can search for "Bronsted-Lowry acid-base theory." This theory states that an acid is a proton donor, while a base is a proton acceptor. It is a widely accepted theory in chemistry and can be found in many textbooks and online resources.

I hope this helps point you in the right direction!