Mechanism of allan's with h2so4, ch3ch2oh

 that the reaction is preferably called an elimination, rather than a dehydration, although I personally like the term dehydration because it emphasizes the strong dehydrating power of H2SO4 that is unfotunately forgotten too often by undergraduates.   I like to think of it as H2SO4 has such a strong affinity for water that it literally pulls water molecules from organics.

The answer to this question is a