Why are HSO4- and H2PO4- amphoteric if they're conjugate bases of strong acids?

[aonin]

Hey guys, on http://www.chemistryhelp.net/basic-chemistry/amphiprotic-substances

I saw that HSO4- (hydrogen sulfate) is a amphiprotic (can accept and donate H+ ions) and therefore acts as a base or acid (amphoteric)

why is this so? Isn't H2SO4 (sulfuric acid) a strong acid and so its equilibrium completely favours the ionisation into HSO4-, therefore HSO4- cannot accept H+ ions to reform back into H2SO4

similarly this happens for H2PO4 (Dihydrogen phosphate ion), so why is it listed as amphiprotic even though H3PO4 is a strong acid and the equilibrium would completely favour ionisation into H2PO4?

So, why are these 2 ions listed as amphoteric even thought they are the weak conjugate bases of strong acids (LB theory)?

Thanks

 

[Ygggdrasil]

You shouldn't believe everything you read on the internet, especially when it contradicts your own understanding.

 

[Gokul43201]

I saw that HSO4- (hydrogen sulfate) is a amphiprotic (can accept and donate H+ ions) and therefore acts as a base or acid (amphoteric)

why is this so? Isn't H2SO4 (sulfuric acid) a strong acid and so its equilibrium completely favours the ionisation into HSO4-, therefore HSO4- cannot accept H+ ions to reform back into H2SO4

similarly this happens for H2PO4 (Dihydrogen phosphate ion), so why is it listed as amphiprotic even though H3PO4 is a strong acid and the equilibrium would completely favour ionisation into H2PO4?

H2SO4 has Ka1 ~ 10^6, but H3PO4 has Ka1 of only about 10^-2. So I think that statement is at least somewhat reasonable for H2PO4-.