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What would be the reaction mechanism for the reaction between epoxide and $\ce{H2SO4}$?

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It would be better if you would propose the mechanism and someone can verify it for you and explain some of the underlying concepts. – jonsca Nov 30 '12 at 2:32
Agreed. In order to give you a better answer, we need to know what about this mechanism you understand and what you don't. – Ben Norris Nov 30 '12 at 11:47

Note that your question could do with some more data. Here is my answer based on what I think you mean:

You ought to get a glycol.

enter image description here

First, a proton from the acidic medium attacks the neucleophile, $\ce{O}$. This creates a positively charged trivalent oxygen. The electrons in one of the two $\ce{C-O}$ bonds transfer to the $\ce{O+}$, breaking the bond and effectively transferring the positive charge to the carbon.

At this point, note that the carbocation thus formed may rearrange.

Now, we have the nucleophilic attack. An oxygen atom (specifically the lone pair of an oxygen) from a nearby water molecule attacks the carbocation, forming another trivalent positively charged oxygen. This is deprotonated, giving the final glycol product.

Here's the same mechanism, showing movement of electrons (pairs):

enter image description here

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