# What would be the mechanism of the given reaction?

I'm tutoring few Class 12 students for their chemistry exams. I'm stuck with few problems. I don't know if the key is wrong or I am wrong.

Problem:

Option (A): Conc. $\ce{H2SO4}$, is an acid, it gives $H^+$ ions which must act like electrophile and add to the double bond, which must produce a carbocation and then, $\ce{HSO_4^-}$ ion must act like a nucleophile and form a bond with the carbocation. Hence, the reaction must be addition of $\ce{H+}$ and $\ce{HSO_4^-}$

Options (B),(C),(D): are bases, with basicity order: (D) > (B) > (C). But what would they do to an alkene?

(A)

How is this so?

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Under (A) you have heat added. What is to stop a second molecule reacting with the first under electrophilic addition to remove the H2SO4 as a good leaving group and give the product shown in the question? –  Nick Jan 14 '13 at 15:36

Bottom line: $\ce{HSO4-}$ is a really bad nucleophile, and it doesn't enter in the picture.