difference between amphoteric and amphiprotic (1 Viewer)

[m_isk]

i know one is a part of the other, but that's about it...

 

[richz]

amphoteric is not in the syllabus but i'll explain it to you anyway.

amphiprotic is similar to amphoteric but amphoteric means a substance which can act with both an acid and a base eg. ZnO +2HCl -> ZnCl2 + H20 and ZnO + 2NaOH + H2O -> Na2Zn(OH)4. So ZnO is an amphoteric substances
Amphiprotic is a substance which can act as a proton donor (acid) and proton acceptor (base) eg. HCO3-
HCO3- + H2O <-> H2CO3 + OH-
AND HCO3- +H20 <-> H3O+ + CO32-

hope that helps

 

[Dreamerish*~]

so you're saying that amphiprotic substances can either donate or recieve protons, in reactions that doesn't necessarily have to be acid-base?

 

[lfc_reds2003]

amphoteric usually refers to oxides

 

[m_isk]

thanks heaps guys!!

 

[natthetubanut]

There are many slight variations of these definitions...

amphoteric (oxide): an oxide that exhibits BOTH acidic and basic qualities.
but other definitions go on to say it can act EITHER as an acid or a base...
eg. water can act as an acid OR a base within a chemical reaction. Therefore it is ABLE to display BOTH acidic AND basic properties.. (prefferably not at one time)

amphiprotic: The substance can both accept OR donate a proton. Thus acting like a base (acceptor) or an acid (donator). eg. monoprotic, polyprotic...etc...

I think they are the best definitions I can come up with. Im not 100% sure if it helps or complexes you any further...Im still coming across various definitions which dont help clarify the issue.

P.S. I think amphoprotic is a different way of sayin amphiprotic...if anyone has a different deffinition.. please tell me. send me a msg!

 

[Steth0scope]

Amphoteric substances can act as bases or acids without necessarily donating/accepting a proton. Thats the difference.

Amphiprotic substances must donate/accept protons.

 

[Undermyskin]

Crap, just think of st. When saying 'acting both like a base and an acid', what's that mean when relating to Bronsted-Lowry's theory when an acid must donate proton and a base must accept proton? So we should keep amphoteric to the earlier definition by Arrhenius?

 

[Steth0scope]

Crap, just think of st. When saying 'acting both like a base and an acid', what's that mean when relating to Bronsted-Lowry's theory when an acid must donate proton and a base must accept proton? So we should keep amphoteric to the earlier definition by Arrhenius?

Substances don't have to donate/accept protons to act as a base or an acid. A basic oxide can react with acids to form salts - for e.g. CuO.

CuO + H2SO4 --> CuSO4 + H2O

Note: there has been no proton donating/accepting but CuO has still acted as a base by "neutralising" sulfuric acid.

 

[Undermyskin]

I just figured out the different right when I posted the question. lolz.

Amphoteric is not necessary to be amphiprotic as amphiprotic involves proton accepting and donating while amphoteric relate to Lewis acids and bases (electron pair accepting and donating respectively). Thus, I've got a sort of diagram

A --> amphiprotic --(Bronsted-Lowry)--> amphoteric

A --> amphoteric --(Bronsted Lowry)--> amphiprotic

or ......................--(Lewis)--> st else.

This is quite cool, isn't it? I think this is similar to your explanation. Thanks anyway.