Yahoo!Answers in chemistry wrote:
The dehydration of 3,3-dimethyl-2-butanol yields 3 different products. Write the equations to show how the carbocation rearranges to explain 2 of the products.
The dehydration can be effected with sulfuric acid or phosphoric acid. The intermediate carbocation can eliminate or rearrange. The rearrangement gives a tertiary carbocation, which is more stable. Elimination for this can give the Zaitsev product, the major product, 2,3-dimethyl-2-butene or a smaller amount of 2,3-dimethyl-1-butene.