Anion Exceptions
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Anion Exceptions
In lecture, Dr. Lavelle stated that very few anions act as acids because it is more difficult for an anion to lose H+. He then mentioned that HSO4- and H2PO4- were exceptions. Can someone explain why these are exceptions to the rule?
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Re: Anion Exceptions
Hi,
HSO4- and H2PO4- were provided as exceptions to the anion guideline since those molecules are amphoteric. HSO4- is derived from H2SO4 following deprotonation and H2PO4- from a deprotonated H3PO4. Both compounds are able to lose another proton (thus acting acidic and increasing pH) or gain another proton (thus acting basic), depending on solution conditions.
HSO4- and H2PO4- were provided as exceptions to the anion guideline since those molecules are amphoteric. HSO4- is derived from H2SO4 following deprotonation and H2PO4- from a deprotonated H3PO4. Both compounds are able to lose another proton (thus acting acidic and increasing pH) or gain another proton (thus acting basic), depending on solution conditions.
Re: Anion Exceptions
HSO4- and H2PO4- are polyprotic acids. More specifically, H2SO4 and H3PO4 are polyprotic, meaning each molecule can donate more than one H+ ion.
Hope this helps!
Hope this helps!
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Re: Anion Exceptions
Hello,
The anions HSO4- and H2PO4- have a negative charge, but are able to act as an acid. Very few anions are able to act as an acid because it is very difficult for an anion to lose a hydrogen. The two exceptions Professor Lavelle gave us are able to give off a proton. For example, NaH2PO4 (which has the anion H2PO4-) is able to give off a proton, potentially two.
The anions HSO4- and H2PO4- have a negative charge, but are able to act as an acid. Very few anions are able to act as an acid because it is very difficult for an anion to lose a hydrogen. The two exceptions Professor Lavelle gave us are able to give off a proton. For example, NaH2PO4 (which has the anion H2PO4-) is able to give off a proton, potentially two.
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Re: Anion Exceptions
Andrew Nguyen 1K wrote:Hi,
HSO4- and H2PO4- were provided as exceptions to the anion guideline since those molecules are amphoteric. HSO4- is derived from H2SO4 following deprotonation and H2PO4- from a deprotonated H3PO4. Both compounds are able to lose another proton (thus acting acidic and increasing pH) or gain another proton (thus acting basic), depending on solution conditions.
This helped a ton! Thank you for explaining!
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