AIEEE 2010 Solved Paper

Whenever dehydration can produce two different alkenes, major product is formed according to Saytzeff rule i.e. more substituted alkene (alkene having lesser number of hydrogen atoms on the two doubly bonded carbon atoms ) is the major product.
Such reactions which can produce two or more structural isomers but one of them in greater amounts than the other are called regioselective; in case a reaction is 100% regioselective, it is termed as regiospecific.
In addition to being regioselective, alcohol dehydrations are stereoselective (a reaction in which a single starting material can yield two or more stereoismeric products, but gives one of them in greater amount than any other).