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Confusing ion[edit]

H3O+??? --mglg(talk) 23:50, 8 December 2006 (UTC)

H3O+ is a hydronium ion. s d 3 1 4 1 5 final exams! 16:08, 16 December 2006 (UTC)

Amphiprotic/Amphoteric substances[edit]

In the page for amphiprotic substancecs, its stated that not all Amphoteric substances are Amphiprotic. I think an example is needed, since the definitions of Amphiprotism (a proton donator or acceptor) and amphoterism (an acid or a base) are very similar and confusing. —The preceding unsigned comment was added by (talk) 07:13, 14 January 2007 (UTC).

I agree with this. I am just learning acids and bases, and I understand them so far as substances that gain or lose protons, so I don't quite see what it means to be amphoteric but not amphiprotic. --— Unbitwise (talk) 23:20, 13 September 2010 (UTC)

I have finally added a section to explain this, with ZnO as an example of amphoteric but not amphiprotic. Dirac66 (talk) 02:41, 30 March 2011 (UTC)

"Amphoteric substances can either donate or accept a proton." Should this be changed to "Amphoteric substances can either donate or accept a pair of electrons."? It seems like they're using the Bronsted-Lowry definition of acids and bases. For instance, Al2O3 (aluminum oxide) is an amphoteric oxide, and it certainly does not have the capability to donate a proton. —Preceding unsigned comment added by (talk) 19:21, 2 April 2011 (UTC)

Yes, the intro was confused too. I have now changed the sentence to Amphiprotic substances can either donate or accept a proton, and clarified in the intro that amphiprotic is only one type of amphoteric. Lewis acidity of metal oxides is mentioned in the final section added a few days ago. Dirac66 (talk) 19:40, 2 April 2011 (UTC)

Duplication of zinc oxide[edit]

Please note ZnO was mentioned twice, first as the first example, then as the final detailed example in "Some other examples include:...". Would someone please pay attention. Biscuit-flower (talk) 06:48, 14 April 2009 (UTC)

Restrict editing[edit]

I dont really think that anyone should be able to add to this page, let alone any pages, because some students use this as a reference and some of this information could be wrong.Bold text —Preceding unsigned comment added by (talk) 21:08, 17 February 2010 (UTC)

Why "mostly"?[edit]

In the article:

Ampholytes are amphoteric molecules that contain both acidic and basic groups and will exist mostly as zwitterions in a certain range of pH.

How about replacing this with:

Ampholytes are amphoteric molecules that contain both acidic and basic groups, acting as zwitterions in a certain range of pH.

I don't what's really true, so I won't make the change, but the original seems vague. (talk) 19:14, 17 January 2015 (UTC)

Mostly is correct, although the article does not explain why. An amino acid, for example, exists as several structures in chemical equilibrium: NH2RCHCO2H + H2O ⇌ NH2RCHCO2 + H3O+ ⇌ NH3+RCHCO2H + OH ⇌ NH3+RCHCO2 + H2O
The phrase exist mostly as zwitterions means that the concentration of the fourth or zwitterionic form of the molecule is much higher than the concentration of the other three forms, which is true for a certain range of pH. This could be more clearly explained in the article. Dirac66 (talk) 19:39, 17 January 2015 (UTC)