So I know that the best Lewis Structure representation of sulfuric acid is one with only single bonds - i.e. sulfur isn't hypervalent.
However, why are the $\ce{S-O}$ and $\ce{S-OH}$ bonds not equivalent then? Why do their lengths differ?
I suspect this has something to do with the addition of the hydrogen on the oxygen atom.
What else could be a cause for the discrepancy?
I ask because my teacher challenged the fact that sulfur might not be hypervalent on the basis that the bond lengths differ.
In retrospect, I think that he:
1) Is placing too much weight on Lewis Structures - which are just rough renditions of what chemicals really are.
2) The $\ce{S-O}$ bonds and $\ce{S-OH}$ bonds may differ in length not because the $\ce{S-O}$ bonds are necessarily double bonded but also because the $\ce{S-OH}$ bonds are different in that S is bound to a hydroxyl group rather than a single oxygen. Also can't there be very minor resonance contributors involving 5-6 bonds on sulfur? It's not that sulfur absolutely can't access its d-orbitals but rather it doesn't to any great extent.