How do sulphurous (H2SO3) and sulphuric (H2SO4) acids compare?

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Offline borat29

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Hello there,
I was wondering if anyone could help me, I need to find out how H2SO3 and H2SO4 can act as acids. And why they can act in this way.

« Last Edit: 19/05/2007 11:48:55 by chris »


Offline Bored chemist

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Both compounds can act as acids by losing hydrogen ions to produce HSO3- ions and SO3-- ions for H2SO3 and (for H2SO4) HSO4 ions and SO4-- ions.
Why they act that way is a bit more complicated. The simplistic view is that the sulphur atom in  the middle of H2SO4 has been oxidised all the way to a (VI) oxidation state by removing 6 electrons; it wants them back. It can get at least a better share of them by removing then from the oxygen atoms round it. When it does this the oxygens in turn are left short of electrons, Two of them can solve this by taking the electron from the hydrogen attached to them. That leaves the hydrogen without an electron ie it leaves an H+ ion.
There's a whole lot more stuff here.
The other acid H2SO3 is rather weaker because, having only lost 4 electrons in the first place, the sulphur is less anxious to get the electrons back.
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Offline tony6789

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nice site helps a if u can read it...
LCPL Hart USMC 6400 I Level Avionics