Does Sulfuric acid donate both of it H+ protons?

  1. H2SO4 + H2O -> HSO4- + H3O+

    A question by a noob.

    I get the fact that water can act as an acid and as a base. The oxygen "pulls" the hydrogen+ ion away from the sulfuric acid oxygen hydrogen bond an gets one itself and becomes positively charged, therefore a hydronium.

    However, I wonder does sulfuric acid donate it`s other proton as well. I see no reason why it wouldn`t I mean it would still be somewhat stable, cause the charge is quite spread out over the 3 oxygen atoms, so more stable more acidic. At least that`s how I am getting it when drawing those resonance structures. When the sulfuric acid molecule would lose both of them, I wonder wouldn`t the sulfuric acid be quite unstable then. And become a base, wouldn`t it just rip out the protons from the oxygen again, because of the size of sulfur in comparison with oxygen.

    The oxygen couldn`t accept another proton, but what about another oxygen?

    People please help me I am in a mess here :(
    If I have stated something from ^^ above please tell me, I am still a underclass rookie.
    Thanks.
     
    Last edited: Oct 16, 2013
  2. jcsd
  3. Borek

    Staff: Mentor

    It can, but HSO4- is a much weaker acid than H2SO4.

    It is all about dissociation equilibria. For example at pH=2.0 there is no H2SO4 in the solution (well, some traces), but concentrations of HSO4- and SO42- are identical (so at this particular pH half of HSO4- donated its proton to water).
     
  4. But it tends to not do it because it is less stable than H2SO4? Because of the negative charge right?
     
  5. But would the HS04- become somewhat basic because of the negative charge?
     
  6. To call it somewhat basic or ''weakly acidic'' are relative terms. It doesn't describe very much. The negative charge doesn't indicate whether something is basic or not, there are just general trends which have many exceptions, but hold for a lot of cases.
     
  7. Could you then shortly explain why acids don`t end up like bases when they give up their protons?
     
  8. They do end up like bases in a sense, they will take back a proton if they can. This happens in many reactions
     
  9. Borek

    Staff: Mentor

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